He should have been warned of the danger—________，but he wouldn’t listen to me

Mary clapped her hand over her mouth_______ she realized what she had said

Using Dr Yuang’s hybrid rice, nowadaysfarmers are producing harvests ________ before.

Tsinghua University,________ in 1911,is home to a great number of outstanding figures.

The USA criticized that China was taking a ____ line with Japan over the Diaoyu Islands dispute.