简述80W/90号润滑油的含义。
参考答案:
W表示冬季用油,两个号连在一起表示多级油,80W/90号油既要满足80W号油的低温性能要求,又要满足90号油的高温黏度要求。
The mid-term exam is only a week from now. We can't________going over our lessons. [ ]
A. take off
B. put off
C. put up
D. cheer up
脘腹痞满,满闷不舒,按之尤甚,但触之无形,可能为
A.胃痛
B.食积
C.聚证
D.痞满
E.臌胀