滚动轴承上没有注出级别代号,说明此轴承的级别为()。
A.C级
B.D级
C.E级
D.G
参考答案:D
He sat at the front ________ be able to hear everything the teacher said.[ ]
A.so as to
B.due to
C.thanks to
D.owing to
锅炉房内必须备有防火砂箱(袋)或化学灭火剂。