There are ten chairs and twelve teachers here. So we need _________ chairs.

The Tibetans have lived in the Himalayas for centuries and have adjusted to the conditions _______.[ ]

The story_________is not boring.

Each boy and each girltalking about optional courses（选修课）.—Yes! And the eachtheir favorite one!

You’d better go there by train.The train ticket isthe airplane ticket.