Question

amt

12番の選択肢はどれになるのでしょうか？ 詳しい解説をお願いします…。

11
O can't have seen
3 needn't have seen
Several people have not come yet. They (
need
Dr
2/may
3 can
12 She (
2 must have seen
4 should have seen
had practiced
3 had been practicing
) harder if she wanted to win the tournament.
2 is practicing
4 should have practiced
) have lost the
4 shall
13 The mayor demanded that a dam (
residential area from being flooded.
built
2 be built
as soon as possib
3 should build
4 bu