问题

Nowhere in nature is aluminium (铝) found free, owing to (由于) its always____with other elements (元素) most commonly with oxygen.[ ]

A: combined
B: having combined
C: combine
D: being combined

正确答案是：

同类题型

I______ myself more－it was aperfect day.

The matter ________ our study surely requires ________ carefully.

He must have finished his homework for a long time, _____ he?

Where is your father–He _______ to Australia on business.

Team leaders must ensure that all members theirnatural desire to avoid the embarrassment associated with making mistakes