牵出线的有效长，一般应不短于该区段运行的货物列车长度的一半，在困难条件下或本站作业量不大时，不应短于（）。
参考答案：200m
I _____ sooner but I didn't know that they were waiting for me.[ ]
A. had come
B. was coming
C. would come
D. would have come
不属于第三方电子商务平台的是（）。
A.淘宝网
B.阿里巴巴
C.宝洁公司网站
D.京东网
