The population of the world in 20th century became very much _________than that in 19th.
Some students in Shanghaie-bags for several months.
May I have a talk with you, sir? I've gotimportant to tell you.
-I really hope to get in touch with Tony.[ -Sorry, I don’t know ___________.
We can do a lot to stay healthy. __________, we should eat a balanced(平衡的) diet.
When you have difficulty, do remember to _________. Two heads are better than one.