The governments are very cautious about setting a new policy and make no decision _____ they are quite sure it is the right one．
| A．because | B．when | C．until | D．as |
I ordered three tickets to the opening ceremony of the 2010 Expo, but none___________me by now.
| A．will reach | B．is reaching | C．has reached | D．has been reaching |
Several minutes after its launch, the X-37B plane successfully sent back its first___________to the control center.
| A．mark | B．sign | C．instruction | D．signal |
You are too___________him. After all he has only been in this field for no more than a year.
| A．mistaken about | B．disappointed at | C．particular about | D．sorry for |
By the time they got to the quake-stricken area, the rescuers___________what difficulty they would have helping the victims out.
| A．sensed | B．had sensed | C．had been sensing | D．were sensing |
Many scientists in the West hold the view that it will be no longer a question soon___________
man can report the earthquakes, volcanic eruptions and tsunamis.
| A．after | B．whether | C．if | D．that |