Số notron trong hạt nhân \[ {}_{13}^{27}Al \] là bao nhiêu?
A.27.
B.14.
C.13.
D.40.

Gọi $m_p, m_n$ và m lần lượt là khối lượng của prôtôn, nơtron và hạt nhân $_{Z}^{A}X$. Hệ thức nào sau đây là đúng?
A.$Z{m_p} + A{m_n} = m.$
B.$Z{m_p} + \left( {A - Z} \right){m_n} = m.$
C.$Z{m_p} + \left( {A - Z} \right){m_n} > m.$
D.$Z{m_p} + \left( {A - Z} \right){m_n} < m.$

Find the word which has a different sound in the part underlined.
A.orbit
B.satellite
C.meteorite
D.microgravity

Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to the following question.
It’s becoming…………..to find a job.
A.most and more difficult
B.more and more difficult
C.more difficult and more
D.more difficult than

Tìm x
x
:  5
=
214
x
=
214
5
x
=
A.×
B.1070
C.
D.

Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to the following question.
_________ we finish the project, _________ we can start the next one.
A.The sooner – the most soon
B.The sooner – the sooner
C.The soonest – the sooner
D.The sooner – the soonest

Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to the following question.
What's that delicious smell?...................(you/cook)?
A.have you been cooking
B.are you cooking
C.had you cooked
D.did you cooked

Find the word which has a different sound in the part underlined.
A.hopeless
B.guess
C.miss
D.museum

Find the word which has a different sound in the part underlined.
A.cooperate
B.telescope
C.rocket
D.microgravity

Find the word which has a different sound in the part underlined.
A.space
B.universe
C.sense
D.mission