单项选择题
We must take a firm __________ against the lowering of ...
单项选择题We must take a firm __________ against the lowering of educational standards．
When he bent over to untie his shoelace，the __________ ...
单项选择题When he bent over to untie his shoelace，the __________ of his trousers split．
We did not find __________ to prepare for the worst con...
单项选择题We did not find __________ to prepare for the worst conditions we might face．
