当冷凝水泡的液面低于()时,将凝水泵置“手动”后,停运
A、1%
B、5%
C、10%
D、20%
参考答案:D
My teacher takes great trouble ______me learn English, since I have a lot of trouble _____it. [ ]
A. helping; learning
B. to help; to learn
C. helping; to learn
D. to help; learning
Text文本框接受的最长字符数由文本框的______属性确定。