. ................. problems in sailing in tropical seas is the coral reefs.
A. One of the biggest
B. The biggest one
C. Of the biggest one
D. There are the biggest
KEY A
Giải thích: one of the + Ns: một trong những...
Dịch: Một trong những vấn đề trong việc đi thuyền ngoài biển nhiệt đới là những rặng san hô.
Hardly any of the paintings at the gallery were for sale, _____?
English has become a second language in countries like India, Nigeria or Singapore where_______ for administration, broadcasting and education.