1—What’s the matter with you You look soworried.– I don’t know ___________ the problem.

The students were advised to try adifferent ________ to solving the complex maths problem.

She studies hard all the time； she never gives up .

I am looking forward_____ some of you guys during my stay in Egypt

The number of new energy vehicles in China’s cities ________ to reach 39,000 by the end of this month, according to Wan Gang, Chinese Minister of Science and Technology