3.3.5The author of this passage seems to believe that ().

1.5题目:The teacher asked each of us () what he had been doing.

1.4题目:Water encourages the () of iron and oxygen to form rust.

1.3题目:I have to book ahead for concert， () are usually held in London.

1.2题目:Can you tell me () about this city that makes people love it so much?

1.1题目:During the () two decades， research has greatly expanded our knowledge about the sleep and dreams.