Working hard is not a only of great success, but it is among the essential requirements.
| A．sign |
| B．signal |
| C．guarantee |
| D．supposition |
（2011重庆卷,27﹚——Silly me! I forget what my luggage looks like.
——What do you think of over there?
| A．the one | B．this | C．it | D．that |
（2011天津卷,1﹚We feel our duty to make our country a better place.
| A．it | B．this | C．that | D．one |
We have various summer camps for your holidays. You can choose ____ based on your own interests.
| A．either | B．each | C．one | D．it |
The two girls are so alike that strangers find ________ difficult to tell one from the other.
| A．it | B．them | C．her | D．that |
（2012陕西卷）No matter where he is, he makes _____a rule to go for a walk before breakfast.
A. him B this C. that D. it