18号道岔允许的侧向通过速度为()。
A、45km/h
B、60km/h
C、80km/h
D、90km/h
参考答案:C
Bobby has been away from the park ________ 8:00 in the morning. [ ]
A. at
B. on
C. for
D. since
水污染的种类:包括__________废水、_________废水和_________废水等。