Videos, recordings and other learning aids are usually used textbooks in language learning

It’s the protection for the trees ___ really matters, _____ how many trees are planted each year.

.I was about to leave_________I saw him_______ towards me, with a bag in hand

We ______ that he explain to us why he was late for the meeting yesterday.[ ]

The new survey shows that the number of students ______ computer games has been increasing in recent years.