从A、B、C、D四个选项中，选出可以填入空白处的最佳选项。
21．----- How about putting some pictures into the report?
----- ________. A picture is worth a thousand words.
A．No way B．It couldn’t be better
C．All right D．Not a bit
22. He spent too much time talking on ______ phone while we were all busy at _____ work.
A. the, / B. a, / C. /, / D. the, the
23.–---Will you go to the history museum tomorrow?
-----Sure I will, ____ it doesn’t rain heavily.
A. in case B. as if C. as long as D. even if
