––Has your brother ever been to the Sand Lake?––Yes, he has _______ the Sand Lake many times.
Some students don’t know how to ____________ stress and become worried.
They had much difficulty ____________ the problem and they needed our help.
You’d better go to bed early. Don’t ____________ too late.
He is very modest and he never ____________.
World War Ⅱ____________ in Europe in 1939.