题目

在牛顿第二定律的数学表达式F=kma中,有关比例系数k的说法正确的是（    ）A.在任何情况下都等于1B.因为k=1,所以k可有可无C.k的数值由质量、加速度和力的单位决定D.k的数值由质量、加速度和力的大小决定 答案：思路解析：在牛顿第二定律的表达式F=kma中,k的数值是由质量、加速度和力的单位决定的,只有质量用千克（kg）、加速度用米每二次方秒（m/s2）、力用牛顿（N）作单位时,k才等于1.答案：C Numbers in different countries may have different meanings. In China, some people think that some numbers bring them________. Take “8” for example, the Chinese pronunciation of the number “8” has almost the________sound as that of the Chinese character “发[fɑ?]”, which means making a fortune. So, many Chinese people spend a lot of________to get their telephone numbers or car numbers to include this number "8". They believe without________doubt that the number will bring them money.________, others don't believe that numbers have anything to do with good luck. They think such an idea is only an ignorant（愚昧的）and superstitious（迷信的）belief. A number is one thing, and good luck is________. They will ask, “________can you ever have any good luck simply because of some lucky numbers, even if you don't work hard, don't have good opportunities and don't get along well with the people around you?”As for me, I________with the latter（后者）. Clearly, lucky numbers are only a kind of superstition. Perhaps it holds true for some cases, but often it does not. Numbers can________bring good luck to a person at all and our fortune is in our own hands. So, everyone can have a good fortune only if he tries his best. Let's always remember "Opportunities are only for the________mind" and "No pains, no gains."1.A.good luck B.had luck C.failure D.bad2.A.different B.same C.similar D.some3.A.time B.money C.things D.dollar4.A.no B.some C.any D.many5.A.However B.What's more C.At last D.But6.A.other B.the other C.another D.others7.A.How B.What C.Why D.Where.8.A.agree B.disagree C.dislike D.like9.A.often B.always C.never D.ever10.A.clever B.lucky C.prepared D.good