lò xo với lực đàn hồi kéo quả nặng lên

20-a

19-b

Không. Vì nhiệt kế y tế thấp nhất là 35 độ C mà nhiệt độ của nước đá đang tan là độ âm. Còn nước đang sôi là hơn 100 độ C mà nhiệt kế y tế cao nhất chỉ 42 độ C nên đo bằng nhiệt kế y tế thì sẽ bị nổ nhiệt kế.

1. I said to Nick, " you don't have to do it right now. You can do it tomorrow".

I told Nam that he didn't have to do it then, he could do it tomorrow

2. he said to them, " Your supervisor will be here in five minutes".

He told them that their supervisor would be there in five minutes

3. She said to me, " I want to lend you my bike, but my mother has broken it yesterday. I'm so sorry."

She told me that she wanted to lend me her bike, but her mother had broken it the day before, she was so sorry

4. The mother said to me, " The sun rises in the East".

The mother told me that the sun rises in the East

tham khảo hình ảnh

-6/7

1.Last week we didn't go to school on Saturday.

2.She isn't at the moment. She is listening to music.

3.Nam often plays basketball in his free time. He doesn't like sports.

4.Tomorrow will her birthday. She will invite some friends to her house.

5.Nam’s mother helped him iron the clothes last night.

6.We spoke to the principal yesterday afternoon.

7.My sister wrote a letter to our aunt in Nha Trang yesterday.

8.I often get up early to take morning exercises every morning.

9.Mr. Lam didn't do morning exercises when he was young. Now he does exercise every morning.

10.Now Hoa is talking to Ba about her recent vacation in Nha Trang.

11.Last week, the Robinsons moved to a new apartment.

12.  Liz will come to visit me next week.

13.  Last week, the dentist filled a cavity in my tooth.

 The Robinsons went to a food stall for lunch last Sunday

ko

Khi hơ nóng nhanh cổ lọ, nó bị nở vì nhiệt, nút bên trong không bị nở, do đó nút lỏng ra.

Khi hơ lâu sau khi cổ lọ nở vì nhiệt, nút bên trong cũng bị nở vì nhiệt, do đó lại bị chặt như cũ.