The accident happened on such an evening with strong winds __________ by heavy rain.

A．appeared

B．happened

C．accompanied

D．mixed

整票货物已经全部装进货舱或装在甲板后，船长或承运人或其授权的代理人凭大副收据所签发的提单是______

A．清洁提单
B．不清洁提单
C．备运提单
D．已装船提单