Jack is really a brave guy — So he is And we can’t admire his courage _____ [ ]

There __________ a big lake near my house. But it’s gone now.–That’s too bad.

Mike is a student from _________, and he studies very ________.

I’m sorry to trouble you, Sir—__________. What can I do for you

Unless _____ to speak, you should remain silent at the conference [ ]