完成句子（共10分，每小题2分）别担心，我一到上海就给你写信。
Don't worry. I'll write to you I get to Shanghai.加强锻炼有益于你的健康。
It your health to take exercise.我经常帮助杰克学英语。
I often Jack his English.昨晚直到父亲回来我才睡觉。
I my father came back last night.学生们花了一个小时才算出这道数学题。
It the maths problem.