Đặt điện áp xoay chiều vào hai đầu một đoạn mạch mắc nối tiếp gồm điện trở R và cuộn cảm thuần thì cảm kháng của cuộn cảm là${{Z}_{L}}.$ Hệ số công suất của đoạn mạch là
A.$\dfrac{\sqrt{\left| {{R}^{2}}-Z_{L}^{2} \right|}}{R}$.  
B.$\dfrac{R}{\sqrt{\left| {{R}^{2}}-Z_{L}^{2} \right|}}$. 
C.$\dfrac{R}{\sqrt{{{R}^{2}}+Z_{L}^{2}}}$.  
D.$\dfrac{\sqrt{{{R}^{2}}+Z_{L}^{2}}}{R}$.

Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to the following question.
Paul Allen is also a ________________ of Microsoft, together with Bill Gates.
A.founder
B.father
C.author
D.architect

Complete the sentences with the correct form of the word in capitals. Choose the best option A, B, C or D
When the MC was introducing my performance, I was at the back of the stage biting my nails ….. (NERVE)
A.nervously
B.nerves
C.nerve
D.nervous

Complete the sentences with the correct form of the word in capitals. Choose the best option A, B, C or D
The matter is so sensitive that everyone in the family has to be very …… what to say. (CARE)
A.carelessly
B.careful
C.carefully
D.careless

Complete the sentences with the correct form of the word in capitals. Choose the best option A, B, C or D
They were ….. to agree and in the end the wife left without saying goodbye. (ABILITY)
A.unable
B.ability
C.ably
D.able

Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to the following question.
English people sometimes named their children after one of their friends or even distant _________.
A.family
B.relations
C.members
D.brothers

Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to the following question.
My great grandfather is over 95 and is ________ pretty poor health these days.
A.of
B.on
C.with
D.in

Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to the following question.
Stephanie seems to be very _______ with her classmates.
A.likable
B.popular
C.known
D.famous

Mark the letter A, B, C, or D to indicate the word(s) OPPOSITE in meaning to the underlined word(s) in the following sentence
The little girl is poorly- educated and she simply doesn’t know how to behave appropriately.
A.ignorant
B.uneducated
C.knowledgeable
D.rude

Điền số thích hợp vào chỗ trống:
Đây là biểu đồ hình quạt cho biết kết quả học tập của một trường học:
 Có% học sinh đạt loại giỏi;
 Có% học sinh đạt loại khá;
           Có% học sinh đạt loại trung bình.
A.30,3
B.48,9
C.30,8
D.