You may go fishing if your work _______.
--- Are you going to take part in the writing competition? ---________. It’s too good a chance to miss.
Uncle Mike _______ to bed ______ he finished his work last night.
Scientists are working hard to make _______ possible for people to live on Mars in the future.
After you see the pictures, you will realize ______ danger the wildlife faces.
--- Middle school students hardly know anything about shopping online, ____ they? --- ________. It’s very popular with teenagers.