Do you think yesterday’s math problem was difficult — Yes. I could work it out.

It’s _________ the boy’s ability to make a lantern _________ a pumpking.

heold couple, but it remains _______ whether they will enjoy it.

______ the extreme levels of air pollution, city authorities have started to take measures to quickly reduce pollution levels and protect city dwellers.

We ________ the project on time without your timely help .