When _______ about their opinion of the effect of modern equipment on their performance of tasks, many young people gave a positive response.

The flu is believed ________ by viruses that like to reproduce in the cell inside the human nose and throat.

(2012·北京高考)________ with care, one tin will last for six weeks.

How did you manage ___________ their approval?

The performance of the host, _________ to please the audience and draw their attention, was greeted with a cold silence, however.