The conflict had developed into a stage ______ the two countries were gathering big troops on the border.
| A．where | B．when | C．which | D．that |
_______they visited the Science Museum, they showed great interest in everything they saw.
| A．For the first time | B．At first |
| C．At the first time | D．The first time |
To their disappointment, they found the lecture given by the professor difficult__________.
| A．to be understood | B．to understand |
| C．understanding | D．understood |
As soon as he heard the ________ news of his death, she _______ tears.
| A．shocked; burst out | B．shocking; burst into |
| C．shocked; burst into | D．shocking; burst out |
----I’m going to the United States.
---- How long ____you ____in the States ？
| A．are; stayed | B．are; staying |
| C．have; stayed | D．did; stay |
He often helps the students _________he thinks are not quick at their studies.
| A．whom | B．whose | C．when | D．who |