These teenagers don't know much of the world;that's why they are easily________.
This is the reason ______he didn't come to the meeting.
The way ______he looks at problems is wrong.
I can never forget the day _______ we worked together and the day ______ we spent together.
I have bought such a watch _______ was advertised on TV.
Last summer we visited the West Lake, ______Hangzhou is famous in the world.