—Where is Jack? — In the sitting room. He _______ TV with his brother.
I am surprised to see you not smoking. You ______.
--- The two old friends were ______ busy ______ with each other ______ the time.--- Yes. They hadn’t met for long.
______ of the students in my class plan to go abroad for ______ study in the future.
Sound travels ______ air ______ a speed of about 340 metres per second.
We knew little about Shu-How Lin, a basketball player from New York Knicks, __________ we watched the basketball matches in NBA. A. until B. if C. when D. because