根据短文内容，用括号内动词的正确时态形式填空。

Liu Xiang was born in Shanghai on the 13th of July, 1983. He is 1.88m tall and 小题1:  (weigh)74 kilograms. He began practicing jumping when he was at Grade Four in primai7 school. He 小题2:  (win) the gold medal of the men’s 110m hurdles in the 28lh Olympic Games. It is the first gold medal that Chinese have won from this competition in the Olympic history. He  小题3:   (be) a great hero in Chinese eyes since then. He also likes singing and seeing films. Once when he小题4: (walk) in the street, he stopped to answer the reporter, "I 小题5: (sing) songs with friends if I feel tired after training, or go to a movie for relaxation."

通常牙体颈部区域的牙周膜面积最大。