1, It's time we went. If we don't leave now, we will miss the train.

2, I know I shouldn't have written to you before , but I have been so busy recently that I haven't had time for writing letters . I should have telephone you instead , but I have forgotten your number.

Trong chân không, các bức xạ được sắp xếp theo thứ tự bước sóng giảm dần là

A. tia hồng ngoại, ánh sáng tím, tia tử ngoại, tia Rơn-ghen

B. tia hồng ngoại, ánh sáng tím, tia Rơn-ghen, tia tử ngoại

C. ánh sáng tím, tia hồng ngoại, tia tử ngoại, tia Rơn-ghen

D. tia Rơn-ghen, tia tử ngoại, ánh sáng tím, tia hồng ngoại

Mạng lưới điện dân dụng có tần số là

A. 50 Hz.

B. 60 Hz.

C. 220 Hz.

D. 0.

Mark the letter A, B, C, or D on your answer sheet to indicate the sentence that best combines each pair of sentences in  the following questions.

Vietnamese culture is dynamic and expressed in various ways. This is due to individual life experience and personality.

A. Vietnamese culture is dynamic and expressed in various ways, according to individual life experience and personality.

B. Vietnamese culture is dynamic and expressed in various ways, owing to individual life experience and personality.

C. Vietnamese culture through individual life experience and personality is dynamic and expressed in various ways.

D. Vietnamese culture is dynamic and expressed in various in individual life experience and personality.