题目内容
（请给出正确答案）
By the time your plane lands tonight, I______at the airport for 3 hours.
A．had waited
B．have been waited
C．had been waiting
D．will have been waiting
安装简答题APP，拍照搜题省时又省心！
更多“By the time your plane lands t…”相关的问题
Scientists said they have found evidence of a giant planet far out in our solar system.In a statement, the California Institute of Technology—Caltech—said this planet travels a very strange “longandthin orbit in the distant solar system.”The discovery was made by two researchers at Caltech: Konstantin Batygin and Mike Brown. They used mathematical modeling and computer simulations (模拟) to find the planet.So far, there have not been any direct observations of the planet. “My jaw hit the floor, ” said astronomer (宇航员) Mike Brown, the moment he realized there might be a ninth planet.
The scientists said it would take this planet 10,000 to 20, 000 years just to make one full orbit around the sun. The new planet, called “Planet Nine ” , has a mass about 10 times the size of Earth.If they are right, the newly found planet would be the ninth planet in our solar system. Pluto (冥王星) had been called the ninth planet until 2006, when it was renamed a “dwarf planet.”
Actual confirmation of a ninth planet would be very big news. “This would be a real ninth planet,” Brown said in the statement. “There have only been two true planets discovered since ancient times, and this would be a third. It&39;s a pretty substantial chunk of our solar system that&39;s still out there to be found, which is pretty exciting.”
While they did not get a picture of “Planet Nine ” yet, the scientists say they are using the biggest—and best—telescopes on Earth to try to find “Planet Nine. ” They are also working on improving their computer simulations. They want to find out more about “Planet Nine’s” orbit, and its impact on the outer part of our solar system.
The newly-found planet ________.
A.moves around the Sun
B.was discovered by two astronomers
C.travels a round orbit
D.is far away from our solar system
The possibility of finding a ninth planet made Mike Brown ________.A.confused
B.frightened
C.satisfied
D.surprised
According to the scientists, ________A.the planet is ten times larger than the Earth
B.ittakes the planet less than 10, 000 yearsto make a full orbit
C.Pluto was once thought to be the ninth planet in the solar system
D.Pluto was given anew name after it was discovered in 2006
It can be inferred from Paragraph 4that ________.A.there is no actual confirmation about the ninthplanet
B.no true planets were discovered in ancient times
C.scientists have found three planets in modern times
D.the ninth planet is the only one discovered since ancient times
To find“Planet Nine”, scientists are using allthe followingEXCEPT ________.A.mathematicalmodeling
B.computer simulations
C.advanced telescopes
D.large spacecrafts
A、fall
B、fall down on
C、fall back on
D、fall in upon
A、neither the theatre or
B、either the theatre nor
C、neither the theatre nor
D、the theatre or
A、three-hours
B、three-hour
C、three-hours'
D、three-hour's
A、initial
B、initiative
C、initiate
D、initialism
A、alive
B、life
C、live
D、lively
A、prime
B、premium
C、principal
D、precious
A、overall gymnast
B、all-rounder
C、generalist
D、comprehensive gymnast
A、provoking
B、productive
C、prosperous
D、plentiful
A、praise
B、loft
C、credit
D、tribute
为了保护您的账号安全，请在“简答题”公众号进行验证，点击“官网服务”-“账号验证”后输入验证码“”完成验证，验证成功后方可继续查看答案！
微信搜一搜
简答题
微信搜一搜
简答题
如搜索结果不匹配，请 
