【题目】We can’t figure out ______ quite a number of insects and birds are dying out．

【题目】From his tired face, I can tell he _______ in the queue for a long time.

【题目】We are ________ by doctors to eat more natural food and take plenty of physical exercises.

【题目】False advertisements play tricks on consumers, thus ______ damage to their legal rights and interests.

【题目】My best friend who _______ a rich man two years ago has a baby now.

【题目】In his fifties, he _______ fishing as his favorite hobby.

【题目】________ on the book, he was attracted by its plot.

【题目】________ around the Water Cube，we were then taken to see the Bird’s Nest．

【题目】— I don't know how to spend my weekend.

【题目】 --- John’s report has been approved by the chief editor.