Câu 1:
Câu tục ngữ “ Một chữ cũng là thầy, nửa chữ cũng là thầy” nói về chủ đề nào trong chương trình GDCD 7 mà em đã học? Em hãy nêu khái niệm và ý nghĩa của chủ đề đó?
Gợi ý: Chủ đề: Tôn sư trọng đạo.

Tính giá trị của biểu thức B = $\frac{5^{2021} - 5^{2019}}{5^{2021} + 5^{2020}}$

Giúp em với ạ 

1. The teacher ______ me as a new member of the class.

A. introduced                        B. introduce                 C. introduction          D. introductory

2. They took a walk to enjoy the _______ of the scenery.

A. beautiful                          B. beautifully                C. beauty                   D. beautify

3. This school is strongly _______ from most others.

A. difference                        B. differently                C. different                 D. differs

4. I wasn't familiar with the _______ of Ho Chi Minh City.

A. geography                        B. geographical           C. geographically        D. geology

5. We arrived two hours ________.

A. lately                                B. late                          C. lateness                   D. latest

6 She was introduced ______ me as a well-known novelist.

A. with                                 B. to                             C. for                           D. in

7. My parents ______ a big-size pizza and some salad online for the dinner.

A. call                                 B. click                          C. order                       D. request

8. Mai had a terrible pain in her neck last night, so she ______ a painkiller.

A. drank                             B. ate                             C. sold                          D. took

9. She pulled out a small silver lighter from her bag. It was too cold in the forest at night. Lighter means ____.

A. something that produces a flame

B. something that can be eaten

C. something to sleep in

D. something to call for help

9. Fansipan is the highest summit in the region. Summit means ______.

A. top                                B. bottom                 C. side                 D. slope

10. The man raised her binoculars to the distant canary across the valley.

Binoculars means ______.

A. an instrument to watch                                  B. a tool to take a photo

C. a device to capture birds                                D. a pair of glasses

Choose the word or phrase that best completes each sentence blow.

1. Every fan of football knows Real Madrid FC. They're the ______ team in the world.

A. most famous                 B. famousest                 C. more famous         D. as famous as

2. This university has a long history. It's the _______ one in my country.

A. more old                         B. older                       C. the most old         D. oldest

3. This photo is the ________ of all.

A. goodest                          B. best                        C. worse                     D. most good

4. Andrew was the ______ of all the students.

A. most hard working                                            C. hardest-working

B. harder-working                                                  D. more hard-working

5. You're the ___ person I know.

A. most lucky                        B. luckyest                C. luckiest                D. luckier

6. The sign at the check-in desk says: "Passengers _______ show their tickets."

A. might                        B. may                              C. must                     D. can

7. The doctor said to him: "You ______ exercise or you certainly have a heart attack again.

A. must                        B. mustn't                           C. don't have to        D. may

8. I ______ forget my key, or I won't get in.

A. must                        B. mustn't                           C. should                  D. don't have to29. You 9_______ go off on your own at night. It's not safe at all.

A. needn't                    B. should                            C. mustn't                 D. must

10. The police told Nick ______ keep his dog under control or she would definitely hurt somebody in the room.

A. could                       B. might                            C. can                       D. must

Choose the underlined part that needs correcting in each sentence below.

1. You don't have to leave your wallet on the bus or you’ll certainly lose it.

                     A                       B               C                                              D                 

2. Friday is the most busy day of all the weekdays.

                 A              B               C                  D         

3. The news were the worst I hear today.

                A      B             C         D

4. It's only ten past. We mustn't hurry. There's lots of time.

       A               B                 C                               D                 

5. The boy doesn't have to touch the tum-on iron. He'll get burned badly.

                              A                                        B       C                         D                 

. Bạn Vinh nói rằng "Trọng lượng của một vật tỉ lệ thuận với khối lượng của nó, nếu khối lượng của vật không đổi thìtrọng lượng của vật không đổi.''. Điểu này có đúng không? 

giúp mình với ạ

-Viết công thức chuyển đổi giữa khối lượng, thể tích, số nguyên tử số phân tử, và số mol?

Help me!! 

Câu 8. Tuy chưa được học về lực nhưng chắc em đã không ít lần nghe nói tới lực. Em có thể xác định được những lực nào trong các hình dưới: