问题
单项选择题
前牙
运循环的功能阶段是（）
A．下颌下降
B．下颌前伸
C．下颌上升，切牙对刃
D．切牙对刃，并滑回至正中
E．下颌下降与前伸
答案
参考答案：D
解析：
切牙对刃切咬食物，穿透食物后，上下切牙对刃，下颌切牙的切嵴沿上颌切牙的舌面向后上方回至正中，由对刃滑回正中是发挥功能的阶段。
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前牙
运循环的功能阶段是（）
A．下颌下降
B．下颌前伸
C．下颌上升，切牙对刃
D．切牙对刃，并滑回至正中
E．下颌下降与前伸
参考答案：D
解析：
切牙对刃切咬食物，穿透食物后，上下切牙对刃，下颌切牙的切嵴沿上颌切牙的舌面向后上方回至正中，由对刃滑回正中是发挥功能的阶段。
Burch has been riding his white horse 4 miles to and from school since(自从)the 83 _____ of the semester. “Every morning, wearing my blue jacket and jeans, I’m on my way at 6 am. ” Burch says, “The streets are mostly 84________ at this time of morning. It’s a nice way to start the day. ” The idea was his 85__________. His family were 86______ their vacation on their farm this summer, “My dad just said, ‘Roby, you 87__________ ride your horse to school every day. ’” says Burch. He thought it really was a good idea. When they got back home, Burch asked for permission from the headmaster (校长), Joe Cox, and surprisingly, he got the green light. Cox 88_______ allowed（允许）Burch to keep the horse next to the headmaster’s house. Then his dad helped Burch find the best route to school. It is along back streets and has 89_________ cars than the others. For the return trip every afternoon, Burch leaves school at 5:45 pm. Even now, as the days grow shorter and colder, he continues to ride his horse. “ I will ride my horse even in the coldest weather. ” he says. Burch says the 90________ time he sat on a horse as a four-year-old boy he was afraid. 91__________ now, “it’s what I do best. ” It’s no surprise that he wants to be a cowboy (牛仔) when he grows up. “I love riding horses more than 92 _______ else. ” He says, “It’s really a guy thing. ” |