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 -样。waste one’s breath“白费口舌”。