柴油机机油稀释的原因有（）。
A.活塞环粘住或磨损过甚
B.采用不合适的机油
C.柴油机温度经常太高
D.燃油进入机油内
参考答案：A, B, C, D
What a table! I've never seen such a thing before. It is _____ it is long. [ ]
A. half not as wide as
B. wide not as half as
C. not half as wide as
D. as wide as not half
如图所示，弹簧测力计的测量范围是 ______N，分度值是 ______N；指针所指的示数是 ______N．
