酱油的卫生问题主要是微生物污染与()问题。A、化学污染 B、生虫 C、生蛆 D、生霉 发布时间:2017-11-13 13:13 │ 来源:www.tikuol.com 题型:单项选择题 问题: 酱油的卫生问题主要是微生物污染与()问题。A、化学污染B、生虫C、生蛆D、生霉
题型:单项选择题 如图所示,光滑的水平面上有两块相同的长木板A和B,长为=0.5m,在B的右端有一个可以看作质点的小铁块C,三者的质量都为m,C与A、B间的动摩擦因数都为μ。现在A以速度ν0=6m/s向右运动并与B相碰,撞击时间极短,碰后A、B粘在一起运动,而C可以在A、B上滑动,问:如果μ=0.5,则C会不会掉下地面? 查看答案
题型:单项选择题 阅读短文,根据短文内容,从短文后的五个选项中选出能填入空白处的最佳选项。选项中有一项为多余选项。 Joe Green is a postman. He works all day and meets his friends in the club in the evening. 1_____. It wasAugust 26th. He was on his way home when he saw a UFO in the sky. Joe got out of his car, and watched it. Finally, it stopped in a park. Joe was very excited. He walked towards the UFO and got in. Then, it took off!Joe was worried. He didn't know what to do. The UFO flew into the sky. 2_____. Joe went home and told his wife the story. She didn't believe him. He went to the police station and told the policeman there. 3_____. Finally, Joe went to the club and told his friends. They laughed at him. A UFO?! A trip into the sky?! They thought it was a joke. Joe didn't care. He knew it was true. 4_____.A. He went swimming after work B. The policeman didn't believe him, either C. After several minutes it returned to the same park D. But there was a strange thing happened last summer E. Now he goes to the same park every night and waits for the UFO 查看答案