Columbus ______ America in 1492. But he didn’t explore it.
A. looked for B. found out C. discovered
______ the dinner was all over, everyone helped wash the dishes.
| A．How | B．When |
| C．Before | D．Why |
Yunnan is beautiful and I’m ______ visiting it again.
| A．keeping clear of | B．suffering from |
| C．looking forward to | D．running away from |
I ______ ride a bike to school. But this morning, I walked to school.
| A．never | B．hardly | C．seldom | D．usually |
Let’s open the windows to have some ______ air here.
| A．cheap | B．nervous |
| C．careful | D．fresh |
--- When ______ you ______ here?
--- Two days ago.
| A．did;come | B．have; come |
| C．will; come | D．do; come |