问题
单项选择题
曲柄连杆机构中，活塞从上止点向下运动，当曲柄转过90°时，活塞下行至冲程长度的（）
A．中点以上
B．中点
C．中点以下
D．难以确定
答案
参考答案：C
搜题请搜索小程序“爱下问搜题”
曲柄连杆机构中，活塞从上止点向下运动，当曲柄转过90°时，活塞下行至冲程长度的（）
A．中点以上
B．中点
C．中点以下
D．难以确定
参考答案：C
Ben Lambert, the famous French singer, 1 a long vacation this summer! He thought about 2 _ to Greece or Spain, but decided 3_ Canada. “I always take 4_ in Europe,” he said. “This time I want to do 5_ . I heard that Canada is beautiful, and I know there are many people there who speak French.” Ben is going to Canada’s Great Lakes. He is leaving the first week _6_ June and staying 7 September. He plans to have a very 8 _ vacation. “I’m taking walks, going fishing, and going bike riding. I’m 9 to spend time in the beautiful countryside. I love nature. I hope I can forget 10_ problems! At night, I’m renting videos and sleeping a lot… A great vacation! I can’t wait!”
|