20. "What can I do for you?" or "May I help you?" is a pet phrase used by _____ .
| A．an assistant engineer | B．an assistant manager |
| C．a helper | D．a shop assistant |
It doesn't matter ________ you turn right or left at the crossing—both roads lead to the park.
| A．whether | B．how | C．if | D．when |
________ was most important to her，she told me，was her family.
| A．It | B．This | C．What | D．As |
It suddenly occurred to him ________ he had left his keys in the office.(2012·江西)
| A．whether | B．where | C．which | D．that |
Have you noticed the problem ________ he is now in low spirits？________ come?
| A．where；What | B．that；How |
| C．in which；For | D．what；As |
When the news came ________ the war broke out，he decided，to serve in the army.
| A．since | B．which | C．that | D．because |