________ was most important to her，she told me，was her family.
| A．It | B．This | C．What | D．As |
Food shortage will long be a worldwide problem _______ much has been done to supply enough for everyone.
| A．before | B．if |
| C．since | D．although |
I do every single bit of housework _______ my husband Bob just does the dishes now and then.
| A．since | B．while | C．when | D．as |
_______ the Atlantic Ocean crosses the equator, the trade winds cause a flow of water to the west.
| A．That | B．When |
| C．Where | D．Though |
To enjoy the scenery,Irene would rather spend long hours on the train _______ travel by air.
| A．as | B．to |
| C．than | D．while |
The pianist waited for silence a while _______ he began to play the violin.
| A．until | B．when |
| C．after | D．before |