习题演练1.I____acat.2.He____adog.3.She____longhair.4.We____abighouse.5.They____ahappyfamily.6.It____ashorttail.7.You____agoodteacher.8.Elva____twobigeyes.9.Tom____aredpen.10.Mymother____abeautifulnose.11.Cats____fourlegs.12.Dogs____(have)twoears.13.Myfather____abluecar.14.Everybody____twohands.15.I____apet.16.Lily____(have)adoll.17.Students____(have)manybooks.18.Girls____(have)manyskirts.19.The...
动词填空题1.LiPingoften_____(read)Englishinthemorning.2._____he_____(clean)thewindowsonceaweek?3.Theworkers_____(have)sportsontheplaygroundnow.4.Howlong___you__(stay)therethedaybeforeyesterday?5.Who_____(listen)tothemusic?6.WhenI____(be)amiddleschoolstudent,Ioften___(sing).7.Hisparents____(go)totheGreatWalltomorrowmorning.8.____they_____(study)Japanesenextterm?9.Whattime_____you_____(do)yourho...
★1、什么叫泵答:通常把提升液体,输送液体或使液体增加压力,即把原动力机的机械能变为液体能量的机器统称为泵。★2、泵的分类?答:泵的用途各不相同,根据作用原理可分为三大类:①容积泵、②叶片泵、③其他类型泵★3、容积泵的工作原理?举例?答:利用工作容积周期性变化来输送液体。例如:活塞泵、柱塞泵、隔膜泵、齿轮泵、滑板泵、螺杆泵等。★4、叶片泵的工作原理?举例?答:利用叶片的液体相互作用来输送液体。例如...