. Để đưa vật có khối lượng 50kg lên cao 2m, người ta dùng mặt phẳng nghiêng dài 4m cần lực kéo là 350N. Tính hiệu suất của mặt phẳng nghiêng?

Choose the best answer.

I think you should buy _____  pack of mineral water instead. And you can also buy _____  snacks such as potato crisps, 3 kilos of mandarins, 2 kilos of apples, 3 bunches of bananas, ______  cookies and soft candies.

Choose the best answer.

We should decorate our living room with _____ orange banner. We also need ________  ribbons, balloons, party hats and costume.

Choose the best answer.

I think that ______ cauliflower is not enough for 3 people. Let’s buy one more.