Question

Many student couldn’t _______, but the teacher _______ the problem by going into a detailed explanation

A. catch up/ cleared away

B. catch up with/ cleared off

C. catch on/ cleared up

D. catch at/ cleared out

Answer 1

Đáp án : C

Catch on = hiểu được; trở nên được ưa chuộng. Clear up something = làm cho rõ ràng, dễ hiểu; dọn dẹp