在下列句子中的空白处填入适当内容或括号内单词的正确形式。
【小题1】_____ (make)different kinds of friends, I joined an online chat group.
【小题2】When a plane is landing, passengers need to keep their seat belts fastened_____ it has come to a complete stop.
【小题3】_____(train) hard to win the spring marathon is the goal which I’m aiming for.
【小题4】I’ve never quite figured out _____ he can still play the piano after his serious hand injury!
【小题5】Because I _____(take) a power nap, I was able to deliver the important speech with a lot of energy.
【小题6】Many famous people sign their name in a way _____ can’t be recognized.
【小题7】Do you remember _____ amazing time we went hiking together in the Rocky Mountains?
【小题8】_____ the future holds for the field of high-speed travel is unknown to us.
【小题9】If one wants to get ahead in his career, he _____ go without some of the comforts of life.
【小题10】I _____(visit) all 50 U.S. states by my 13th birthday next month, becoming the youngest person ever to do so.