空调压缩机不能启动的原因有（）
A、排气压低；
B、排气止回阀泄漏；
C、机腔内积由或液体过少
参考答案：B
Though he started late, Mr Guo played the piano as well as, if , Miss Liu. [ ]
A. not better than
B. not better
C. no better than
D. no better
月季黑斑病只侵害叶片，不侵害茎干和花梗、花萼。
