In order to make up for the lost time, they are working ______.
______ is often the case, we have worked out the production plan.
The flu is believed _____by viruses that like to reproduce in the cells inside the human nose and throat.
—How did you find the talk this morning? —______.
The flowers _________sweet in the botanic garden attract the visitors to the beauty of nature.
—You have made progress in your English study, haven’t you?—Yes, but much ____. A remains to do B is remained to doC remains to be done D is remained to be done