Philip has gone to New Zealand．

Oh，can you tell me________?

A．when did he leave

B．when he is leaving

C．when he left

D．when is he leaving

地下工程卷材防水层的施工方法大多采用（）。

A.外防内贴法

B.外防外贴法

C.内防内贴法

D.内防外贴法