Only when I checked the paper once more _________ there was a mistake.
| A．I realized | B．did I realize | C．I had realized | D．had I realized |
The angry boy looked at his mother and shouted out the words ________ in his heart for many years.
| A．having been hidden | B．hidden | C．hiding | D．to hide |
--- Any good way to get there on time? ---Only by ________.
| A．speeding up | B．turning up |
| C．taking up | D．putting up |
You must read the _______ with great care to see if the drug contains PPA before it is taken.
| A．instructions | B．introductions | C．explanations | D．Expressions |
It is global warming, not other things ________ the extreme weather.
| A．that have led to | B．which has caused |
| C．which are causing | D．that has led to |
Its great contributions ________ the development of a modern China will never be forgotten.
| A．by | B．to | C．for | D．with |