单项填空
从A、B、C、D四个选项中，选出可以填入空白处的最佳选项，并在答题卡上将该项涂黑。
21．It rains very heavily in this area, which has _______ annual rainfall of 7,000 mm, _______ ideal environment for forests．
A．the; an B．an; 不填 C．an; an D．不填; the
22．I think he’s determined that he won’t give in — see if you can _______the stubborn man．
A．get round B．wipe out C．take over D．see through
23．The islands developed on their own for 80 million years and _______ have many rare animals found nowhere else．
A．soon B．so C．early D．yet
