Trong những năm 1918 – 1923, phần lớn các nước tư bản chủ nghĩa tình hình kinh tế như thế nào?

A. Ổn định và phát triển

B. Tương đối ổn định

C. Lâm vào tình trạng khủng hoảng.

D. Khủng hoảng trầm trọng và kéo dài.

Last year, my summer vacation lasted for 1 months. I and my friends travelled a lot of beauty spots in Vietnam. But the tour to Sapa impressed us most of all. 
First, we were really interested in the natural charm of Sapa. We visited many breathtaking landscapes in SP such as: Bạc waterfall, Ham Rong bridge, Ta Phin village. … SP had a natural beauty with imposing moutains, white clouds expanding into horizon,..Especially, the air in this small town was so fresh and cool. We liked the feeling of walking along the streets at night and ate the roasted-foods. You could feel the air of winter even in summer if you were in SP at night. 
Besides, SP was attracted us due to the variety of culture. Along the street in this beautiful town, we could see ruddy-cheeked women and children from the region’s ethnic minorities. All of them were dressed in their traditional garb. One thing made us surprised that they could talk to foreign tourists with spoken-English fluently and quiet precisely. We learned many interesting things about the custom and culture of different minorities in North-Western Vietnam.
Coming back to Hanoi, we still couldn’t forget the trip to SP. It made our summer vacation last year unforgettable.

Các hồ nhân tạo:
-Hồ Trị An
-Dầu Tiếng
-Hố Xoài
-......

Có tác dụng:
-Thủy Điện
-Du Lịch
-Tưới hồ tiêu
-.......
 

Một vật dao động điều hòa tắt dần. Cứ sau mỗi chu kì biên độ dao động giảm 2%. Hỏi sau mỗi chu kì cơ năng giảm bao nhiêu

A. 1,00%.

B. 3,96%.

C. 2,00%.

D. 4,00%.