不透明瓷过薄可致（）
A.气泡
B.裂纹
C.色泽不佳
D.牙体层附着不良
E.金瓷冠口内崩瓷
参考答案：C
For some time now, world leaders _____ out the necessity for agreement on climate change, the world economy and African development．
A．had been pointing
B．have been pointing
C．were pointing
D．pointed
某进口公司承揽一笔来料加工业务，委托某个体企业加工，该个体企业可以以自己的名义向海关办理报关手续。( )
