Trong không gian, cho tam giác ABC cân tại A, A B = a 10 ,   B C = 2 a Gọi H là trung điểm của BC. Tính thể tích V của hình nón nhận được khi quay tam giác ABC xung quanh trục AH.

A.  V = 2 πa 3

B. V = 3 πa 3

C. V = 9 πa 3

D. V = πa 3

Read the passage carefully then decide whether the following statements are true (T) or false (F).

Nam likes sugar and sweet things. He often has an ice-cream and a chocolate cake after meals, but he only cleans his teeth once a day. He doesn’t like going to the dentist. Yesterday, Nam went to see the dentist because he had a terrible toothache. The dentist filled his tooth and gave him some medicine. The dentist told him not to eat too much sugar and he should brush his teeth after meals.

____ The dentist filled his tooth and gave him some medicine.