The Nuclear Security Summit is an initiative of Mr. Obama, considers nuclear terrorism to be one of the greatest threats to international security.
| A．which | B．what | C．who | D．whom |
__________ full preparations, we decided to put off the meeting till next week．
| A．We did not make | B．Having not made |
| C．We had not made | D．Not having made |
You ________ pay too much attention to your reading skill, as it is so important．
| A．can not | B．should | C．must | D．needn't |
In such dry weather, the flowers will have to be watered if they ____________
| A．have survived | B．are to survive |
| C．would survive | D．will survive |
It is the protection for the trees___________ really matters, rather than how many trees are planted．
| A．what | B．that |
| C．不填 | D．which |
We can’t go on with the experiment because the computer_________．
| A．hasn’t been repaired | B．hasn’t repaired |
| C．is not repaired | D．hadn’t been repaired |