We like the man ________works very hard and helps others very often.

We can have ___ bluer sky if we create ___ less polluted world.

Mr. Li, I can’t understand everything in class.—Don’t worry! I’ll ________ the main points at the end.

He always looks ________. Now he is looking ________at his new drawing.

Miss Liu, do you have any ideas about Jiuzhaigou _______ we will play together this summer holidays?