22．Lawrence Craven, a doctor from the USA，is the author of several published reports, one of______ introduced the idea in 1953 ______aspirin could reduce the risk of heart attacks．

---The vase cost me almost 100 yuan. ---Well, it was crazy of you to spend so much money _____you could buy a much         cheaper one.

On June 16, 2012, it arrested the world’s attention ______ Shenzhou9 spacecraft was successfully sent into the sky with the first Chinese woman astronaut. 

 —What should we pay more attention to if we go north in winter, Mum?—Nothing much. Take warm clothes________ the weather is cold.

_______ I admit that there are still some problems about the traffic in this area, I don't mean that it can't be solved.