Dear Mrs Brian,

I (Example: am) sorry but I can't come to your class (1)__much______ more because I have (2)____to____ return to my country. My sister is going to get married(3)______next__ month. I want to go shopping (4)___with______ her to choose a dress. My parents (5)____are _____ going to make a big meal for the guests and there will(6)_______be__ a lot of work in the kitchen.

I'm sorry I (7)_____will____ leave the English class. You are (8)____a____ very good teacher. Please (9)____say_____ goodbye to the other students for (10)__me_____.

Thanks again.

Best wishes,

Soraya

Tính các tổng dưới đây sau khi đã rút gọn phân số :

a)\(\dfrac{7}{21}\) + \(\dfrac{9}{-36}\) = \(\dfrac{7}{21}\)+\(\dfrac{-9}{36}\)=\(\dfrac{1}{3}\)+\(\dfrac{-1}{4}\)=\(\dfrac{4}{12}\)+\(\dfrac{-3}{12}\)=\(\dfrac{1}{12}\)

b) \(\dfrac{-12}{18}\)+\(\dfrac{-21}{35}\)=\(\dfrac{-2}{3}\)+\(\dfrac{-3}{5}\)=\(\dfrac{-10}{15}\)+\(\dfrac{-9}{15}\)=\(\dfrac{-19}{15}\)

c) \(\dfrac{-3}{21}\)+\(\dfrac{6}{42}\)=\(\dfrac{-1}{7}\)+\(\dfrac{1}{7}\)=0

d) \(\dfrac{-18}{24}\)+\(\dfrac{15}{-21}\)=\(\dfrac{-18}{24}\)+\(\dfrac{-15}{21}\)=\(\dfrac{-3}{4}\)+\(\dfrac{-5}{7}\)=\(\dfrac{-21}{28}\)+\(\dfrac{-20}{28}\)=\(\dfrac{-41}{28}\)

Mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the following questions.

Though built in 1946, computers were sold ______ for the first time in the 1950s

A. Commercial 

B. commercialise 

C. commercially 

D. commerce