Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to the following question.
That machine is useless. It _____not been used for a long time
 
A.has
B.was
C.did
D.is

Kết luận nào dưới đây không đúng?
A.Độ phóng xạ là đại lượng đặc trưng cho tính phóng xạ mạnh hay yếu của một chất phóng xạ.
B.Độ phóng xạ là đại lượng đặc trưng cho tính phóng xạ mạnh hay yếu của một lượng chất phóng xạ.
C.Độ phóng xạ phụ thuộc vào bản chất của chất phóng xạ, tỉ lệ thuận với số nguyên tử của chất phóng xạ.
D.Độ phóng xạ của một lượng chất phóng xạ giảm dần theo thời gian theo quy luật hàm số mũ.

Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to the following question.
The manager wanted the workers _______ the machine to a new station.
A.to move
B.moving
C.move
D.moved

Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to the following question.
Instead of buying a new computer, why don’t you have your old one _______?
A.to fix
B.fixing
C.fixed
D.fixes

Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to the following question.
Lots of houses _______ by the earthquake.
A.were destroying
B.were destroyed
C.destroyed
D.are destroying

Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to the following question.
My brother got his laptop ____________ as it was still under warranty.
A.to serviced
B.serviced
C.servicing
D.to be serviced

Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to the following question.
Your tooth is very decay. You should see a dentist and have it _______ .
A.to be pulled out
B.to pull out
C.pull out
D.pulled out

Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to the following question.
The company had someone _______ all the junk in the store.
A.to clear out
B.clear up
C.to clear up
D.clear out

Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to the following question.
NASA has had an autonomous spaceship _____ the universe recently.
A.to explore
B.explored
C.exploring
D.explore

Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to the following question.
The robot manufacturer had his customers _______ their outdated robots for the next generation robots.
A.exchanged
B.exchange
C.to exchange
D.exchanging