21£®I asked Tom and Mike to come to my birthday party£¬but _____appeared£®

A£®either    B£®neither        C£®both   D£®none

22£®At the meeting£¬they talked about ____harm pollution does to the environment and the people around£®

A£®which    B£®why    C£®how   D£®what

23£®Whether you like it or not£¬we live in a particular community _______exchanging presents is an important part of communication£®

A£®which    B£®that    C£®when   D£®where

24£®—______you interrupt now? Can’t you see I'm busy with my work?—Sorry Sir£¬but it’s urgent£®

    A£®Can    B£®Should    C£®Must        D£®Would

25£®—Hi£®Dave£®This is Helen speaking!

    —Hi£¬what a coincidence! I ____about you£®

A£®was just thinking         B£®just thought  C£®have just thought             D£®would just think