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

an we go outing in this kind ofweather!”! Bob said,__________ out of the window

I’d like to know __________or not.

What do you think of the film called So Young — I think this is the most wonderful film _______ I have ever seen.

The committee ______five members, _____one elderly and two middle-aged comrades.