tìm x:
$\frac{x}{15}=\frac{-3}{11}\times \frac{77}{36}$

Lực ma sát là lực tiếp xúc hay không tiếp xúc? Vì sao?

Tính hợp lí
B= $\frac{4}{21}+\frac{4}{77}+\frac{4}{165}+\frac{4}{285}$

Fill in the blanks with “will or might"
1. Tomorrow it ....... rain in the north-west. The weatherman has said that.
2. My friend be 12 next Monday. She has told me about it.
3. Hey John! Wait a minute. I have a word with you.
4. I don't know. I ............. go to the party. (negative)
5. I'm going to take a coat. It...... be cold later.