Khi tần số dòng điện xoay chiều chạy qua đoạn mạch chỉ chứa cuộn cảm tăng lên 4 lần thì cảm kháng của cuộn cảm sẽ 

A. tăng lên 2 lần

B. tăng lên 4 lần

C. giảm đi 2 lần

D. giảm đi 4 lần

2.A popular festival you know.

In Vietnam, there are many traditional as well as modern festival from foreign countries, but the festival I like best, is a very popular festival: Mid-Autumn festival.It starts every full moon in August in Vietnam.Everybody will eat mooncakes-a kind of cake indispensable in this festival.In the evening, children will go out for a lantern parade.Somebody go out for a walk or go out to buy some mooncakes from the market.Outside, the roads will be light up by the lights of the lantern parade.Looks it's very beautiful and shimmer all the time. It's so interesting!That's what I think, how about you?