我国太阳能、地热能、水能都丰富的地区是()

认为封建君主是“天下之大害”的思想家是()

有①氨水②NH4Cl溶液③Na2CO3溶液④NaHCO3溶液各25mL，物质的量浓度均为0.1mo1/L，下列说正确的是

“Earlytobed，earlytorise”makesamanhealthy,wealthyandwise.It'sgoodforthebody.Thisisanoldsaying.Haveyouheardofitbefore?Itmeansthatwemustgotobedearlyatnight，andgetupearlyinthemorning.Thenweshallbehealthy.Weshallalsoberichandclever.Thatistrue.Thebodymusthaveenoughsleeptobehealthy.Childrenofyoungageshouldhaveenoughsleep，ortheycan'tdotheirworkverywell.Theywillnotbewiseandtheymaynotbecome。wealthy!.Thebodyalsoneedsexercise:walking,running,jumping,swimming,playinggamesandallother。exercise.Exercisekeepsthebodystrong.Exercisealsohelpsthebloodtomovearoundinsidethe.body.Thisisveryimportant.Ourbloodtakesfoodtoallpartsofourbody.Theheadalsoneeds.blood.Exercisehelpsustothinkbetter.

根据短文内容，回答问题.

1.Whatdoes“earlytobed.earlytorise”mean?

2.Whatmustthebodyhavetobehealthy?

3.WhatwillhappentoChildrenofyoungagewhodon'thaveenoughsleep?

4.Whatkeepsthebodystrong?

5.Whattakesfoodtoallpartsofourbody?

静止在光滑水平面上的物体，受到水平外力F作用，F随时间按正弦规律变化，如图所示，图中t1到t7各时刻将0～t8这段时间等分为8段，在t=0时物体由静止开始运动，则()