某中学生针对某些植物组织培养时间长、观测困难等问题,运用光合作用和自动化控制原理,研制出“自动化植物组织培养机”,通过对机器内部温度、湿度、光照、臭氧、二氧化碳等因素进行实时检测、调试和补充,使原有缺陷得以克服。这说明( )
several times in the exam,John didnt have much confidence in himself.
—The problem wasn’t difficult for him,was it? —No,it wasn’t.Hea more difficult one.
Let me take care of your little dog while you are away,?
I met Julia the other day.It was the first time weeach other since we graduated from school.
At about 9 p.m.,we came toold templeeast of the town.