问题
单项选择题
Don't argue with him any longer. You are only wasting your breath ______ to win him over to your side.
A．having tried
B．to try
C．to be tried
D．trying
答案
参考答案：D
解析：waste...on sth. 或waste...doing sth. ，用法同spend一样。waste one's breath“白费口舌”。