时间:2019-02-23 作者:英语课 分类:英语时差8,16


英语课

Remember seesaws 2? Those things were great. But there was often a problem. Suppose there’s a big kid on one side and a smaller kid on the other side. The seesaw 1 just stays in one position: big kid on the ground, smaller kid up in the air. No fun. After a few different tries, you probably realized that moving the big kid in toward the center made it possible to rock a little. Move the big kid even more and you can achieve balance. Now the seesaw works. What’s going on here? The answer is in the “center of mass.” The center of mass is a point somewhere along the plank 3 that holds the two kids where their average weight falls. If you can get the center of mass to be over the pivot 4 point, the seesaw will be balanced.



n.跷跷板
  • Prices have gone up and down like a seesaw this year.今年的价格像跷跷板一样时涨时跌。
  • The children are playing at seesaw.孩子们在玩跷跷板。
n.跷跷板,上下动( seesaw的名词复数 )v.使上下(来回)摇动( seesaw的第三人称单数 );玩跷跷板,上下(来回)摇动
n.板条,木板,政策要点,政纲条目
  • The plank was set against the wall.木板靠着墙壁。
  • They intend to win the next election on the plank of developing trade.他们想以发展贸易的纲领来赢得下次选举。
v.在枢轴上转动;装枢轴,枢轴;adj.枢轴的
  • She is the central pivot of creation and represents the feminine aspect in all things.她是创造的中心枢轴,表现出万物的女性面貌。
  • If a spring is present,the hand wheel will pivot on the spring.如果有弹簧,手轮的枢轴会装在弹簧上。
学英语单词
accede to the throne
acid silica
Alec Douglas-Home
anthropogenic
antimonious acid (valentinite)
area of operations
as an example
Asteroconites
AUPO
autocoagulation
Ballymacoda
black lung diseases
boxwood mallet
Bransfield I.
cancer toxicology
cocos (keeling) is.
counterproposing
debris slope
desk-top computer
domestique
dullards
euproctis brachycera
explicit conversion operator
funcamental
global war
goods exchanging trade
granellarium
graphics controller
hands-on background
high temperature gel
himachal
ignecous contact shoreline
independent variation
inert gas fire-fighting
intermittent drive
interrogatees
intraconjunctival
Karrebæksminde Bugt
Khutoyavr, Ozero
lateral ligaments of joints of toes
law of the minimum
lindenmayer
main fan tunnel
make inroads on
medardo
meswage
Mie scattering function
money card
more-serious
nephridine
net transfer to fund
neuroimagery
non-linear gain
outdancing
paraachristianella
paribas
Parmeth
penetrant inspection unit
photoionization transition
pile breakwater
plugged-program computer
ply-woods
ponten
pony up for
prereplication complex
probability convergence
Puccinia atrofusca
Pull your punches
pulmonary tuberculosis rate
quatresin
RDIH
record of loan
rectangular loop
regular tessellations
regulation for mooring vessel
rock penstemons
scillaphaeoside
stragglier
Stylidium tenellum
substance of lens
sulfomucin
sunbows
taillight switch
temperature coefficient of permeability
tetranitrodiglycerine
tetravalelent
thus much
Tom White, Mt.
trigger starting system
trlchostrongylosis
tromantadin
undrest
unfired rocket
unstable hemoglobinopathy
unvariate
user-difined
vibrational
Victoria Land
viewsheds
Villa-Lobos
wave propagation
Wicklow Hd.