Lai Changxing _____ Canada with his family before the policemen began to catch him. [ ]

A. had been to

B. has gone to

C. would go to

D. had arrived in

钻机停钻，必须将钻头提出孔外，置于钻架上，严禁将钻头停留孔内过久。这种做法是否符合安全施工的要求（）。

A.前半部分错误，后半部分正确

B.错误

C.前半部分正确，后半部错误

D.正确