plant species that are well adapted to survival in dry climates are being looked at for an answer in developing more efficient crops to grow on marginally arable lands.
Plants use several mechanisms to ensure their survival in desert environments. Some involve purely mechanical and physical adaptations, such as the shape of the plant's surface, smaller leaf size, and extensive root systems. Some of the adaptations are related to chemical mechanisms. Many plants, such as cacti, have internal gums and mucilage which give them water-retaining properties. Another chemical mechanism is that of the epicuticular wax layer. This wax layer acts as an impervious cover to protect the plant. It prevents excessive loss of internal moisture. It also protects the plant from external aggression, which can come from inorganic agents such as gases, or organic agents which include bacteria and plant pests.
Researchers have proposed that synthetic waxes with similar protective abilities could be prepared based on knowledge of desert plants. If successfully developed, such a compound could be used to greatly increase a plant's ability to maintain health in such adverse situations as inadequate water supply, limited fertilizer availability, attack by pests, and poor storage after harvesting
It can be inferred that synthetic stimulate waxes________
A. have been determined to be impervious to organic and inorganic agents
B. have not succeeded
C. have not been developed yet
D. have the quality of causing bacteria
Giải bởi qa.haylamdo.com
Đáp án C
Đ3: Researchers have proposed that synthetic waxes with similar protective abilities could be prepared based on knowledge of desert plants. If successfully developed.
Chú ý cụm từ: If successfully developed : câu trên đang nói đến các nhà nghiên cứu nói về synthetic
waxes, câu dưới nói: nếu phát triển thành công -> nghĩa là vẫn chưa phát triển được
Read the following passage, and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions.
Revising for exams is not as easy as it looks. You will need to work out which routine suits you best, and then stick to it. Some people like studying at night when it’s quiet, whereas others find the early morning is a good time to get things done. You might enjoy ___ (1) ____ to music while you revise, but this can be ___ (2) ___. Can you really concentrate ___ (3) ____ two things at once? So think ___ (4) ____ you turn your radio on.
Your ___ (5) ____ is also important while you are revising. This may be a more than usually ___ (6) ____ period of your life, when you should take extra care to eat properly. No missed meals, or junk food, or ___ (7) ____ cups of coffee! Get plenty of exercise as well. If you have got fed up with ___ (8) ____ you’re doing, or find it hard to concentrate, go for a walk to clear your head. ___ (9) ____ exercise will help to keep your body fit and your brain working ___ (10) ____.
Finally, you also need to take time off. Go out occasionally, see your friends, make time to relax. Then you will return to your studies fresh and full of enthusiasm.Question 10
Read the following passage, and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions.
Revising for exams is not as easy as it looks. You will need to work out which routine suits you best, and then stick to it. Some people like studying at night when it’s quiet, whereas others find the early morning is a good time to get things done. You might enjoy ___ (1) ____ to music while you revise, but this can be ___ (2) ___. Can you really concentrate ___ (3) ____ two things at once? So think ___ (4) ____ you turn your radio on.
Your ___ (5) ____ is also important while you are revising. This may be a more than usually ___ (6) ____ period of your life, when you should take extra care to eat properly. No missed meals, or junk food, or ___ (7) ____ cups of coffee! Get plenty of exercise as well. If you have got fed up with ___ (8) ____ you’re doing, or find it hard to concentrate, go for a walk to clear your head. ___ (9) ____ exercise will help to keep your body fit and your brain working ___ (10) ____.
Finally, you also need to take time off. Go out occasionally, see your friends, make time to relax. Then you will return to your studies fresh and full of enthusiasm.Question 6
Read the following passage, and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions.
Revising for exams is not as easy as it looks. You will need to work out which routine suits you best, and then stick to it. Some people like studying at night when it’s quiet, whereas others find the early morning is a good time to get things done. You might enjoy ___ (1) ____ to music while you revise, but this can be ___ (2) ___. Can you really concentrate ___ (3) ____ two things at once? So think ___ (4) ____ you turn your radio on.
Your ___ (5) ____ is also important while you are revising. This may be a more than usually ___ (6) ____ period of your life, when you should take extra care to eat properly. No missed meals, or junk food, or ___ (7) ____ cups of coffee! Get plenty of exercise as well. If you have got fed up with ___ (8) ____ you’re doing, or find it hard to concentrate, go for a walk to clear your head. ___ (9) ____ exercise will help to keep your body fit and your brain working ___ (10) ____.
Finally, you also need to take time off. Go out occasionally, see your friends, make time to relax. Then you will return to your studies fresh and full of enthusiasm.Question 2
Alex is going to take extra lessons to_____ what he missed while he was away
Mark the letter A, B, C, or D on your answer sheet to indicate the underlined part that needs correction in each of the following questions
Bella had better (A) to change her study habits if she (B) wants to be admitted (C) to (D) a good college
No sooner ______ into the bath than someone knocked at the door
Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the questions.
Water scarcity is fast becoming one of the major limiting factors in world crop production. In many areas, poor agricultural practices have led to increasing desertification and the loss of formerly arable lands. Consequently, those plant species that are well adapted to survival in dry climates are being looked at for an answer in developing more efficient crops to grow on marginally arable lands.
Plants use several mechanisms to ensure their survival in desert environments. Some involve purely mechanical and physical adaptations, such as the shape of the plant's surface, smaller leaf size, and extensive root systems. Some of the adaptations are related to chemical mechanisms. Many plants, such as cacti, have internal gums and mucilage which give them water-retaining properties. Another chemical mechanism is that of the epicuticular wax layer. This wax layer acts as an impervious cover to protect the plant. It prevents excessive loss of internal moisture. It also protects the plant from external aggression, which can come from inorganic agents such as gases, or organic agents which include bacteria and plant pests.
Researchers have proposed that synthetic waxes with similar protective abilities could be prepared based on knowledge of desert plants. If successfully developed, such a compound could be used to greatly increase a plant's ability to maintain health in such adverse situations as inadequate water supply, limited fertilizer availability, attack by pests, and poor storage after harvesting
This passage deals mainly with ________
Her mother, ______ has been working for thirty years, is retiring next month
In the hotel lobby, the detective caught ______ of the man whom he had been hired to follow
Mark the letter A, B, C, or D on your answer sheet to indicate the underlined part that needs correction in each of the following questions
You (A) should stop (B) to smoke because it is very harmful (C) to (D) your health
Hardly had he stepped out of the room _________ he heard a loud laughter within
