—I wonder     Tom will come to our party.—He will when he finishes his work, I think.

 None of the shoes in the shops are the right size. They are _____too big ____too small.

 Mary sings English songs well and ______.

David didn’t give up ______ he had failed in the experiment four times．

—You won’t pass the oral English test ______ you practise speaking more．—I am sure that I will be the best．Don’t worry，mum．