This means that for the first time doctors may be able to tell if an infected（被感染的）person who feels well is ________ becoming ill, so that they can try to do something to prevent this

Thechairman thought ________ necessary to invite Professor Smith to speak at themeeting.

The bill would ________workers twelve weeks of unpaid leave for family emergencies.[ ]

I’m told that our plane will at least delay 3 hours. —What do you think has happened? —It is said to have been _______ by a terrible storm.

Peter realized Linda didn’t want to connect with him as usual what he had said to her