We plan to reach the North Pole in mid-July, and by then we _______ for six weeks

Xiao Hong worked harder last year _______ , she still didn’t get high grades[ ]

By the time he was ten, Edison _________ experiments in chemistry.

I couldn’t wait _____ the box as soon as I receivedthe gift.

Was it in the village ______ he was born ________ thetalented journalist met the retired professor