17000 bài tập tách từ đề thi thử môn Tiếng Anh có đáp án (Phần 3) (Part 2)

The lecture was so boring that John could hardly keep himself asleep.

48/500

The lecture was so boring that John could hardly keep himself _____________ asleep.

of falling

to falling

from falling

in falling

Giải thích

Chọn C