40. Helen will help you as soon as she finishes(finish) that letter.
41. Tom (sit)was sitting in a cafe when I saw him.
42. Since I was(be) a child, I have developed an interest in wild animals.
43. We will send you the goods as soon as we receive (receive) your cheque.
44. By the time you give (give) the children their meal, your dinner will be cool.
45. After Jane finishes (finish) her degree, she intends to work in her father's company.
46. Jenny Tran have never heard (never hear) about Halloween before she came to the US.
47. I'll take the paper with me. I'll read it while I am waiting (wait) for the bus.
48. When the light went out, I was lighting (light) some candles.
49. The message arrived after I had left (leave).
50. By the time my mother retires, she has saved(save) 20,000 US dollars.