1. Is it ....difficult..to answer that question? ( difficulty)

2. Tom's listening is..excellent...( excellence)

3. Do you take....interest.....In watching English TV programs? (Interested)

4. What are your ..favourite..English songs? ( favour)

5. You ought to give reasons for your....choice(s)..........( choose)

6. Peter worked ...hard......and passed the exam ( hardly)

7. My sister is working for a ..national/ international....bank in HCM city ( nation)

8. We are looking forward to..hearing....from You ( hear)

9. The news worried them, and they were unhappy

-> It was such worrying news that it made them unhappy / It was such unhappy news that it worried them

10. We can always check this machine before we use it

-> I suggest checking this machine before we use it.

Hoặc: I suggest that we (should) check this machine before we use it.

gọi số đó là abc, sau khi viết số 0 thì thành a0bc

abc x 9 = a0bc

abc x 9 = a x 1000 + bc

abc x 9 = a x 1000 + bc

a x 100 + bc x 9 = a x 1000 + bc

bc x 8 = a x 900

để 6a37b chia hết cho 2 ; 3 ; 5 thì b phải bằng 0

để 6a370 chia hết cho 3 thì a = { 2 ; 5 ; 8 }

vậy a = 2 ; 5 ; 8

b = 0