China supplies more than 90 percent of the world’s rare earth metals, but its reserves only ________ about one-third of the world’s total.

______ difficult it is, he is determined to ______ the experiment.

Tom likes doing things with his family. He’s learned much from ___ His family help him a lot.

I don’t make ________ clear when and where the parents’ meeting will be held.

A: Where are you now?B: We _________ on the Great Wall of China and talking to you.