Vẽ hai góc kề bù xOy và yOz, biết  x O y ^ = 70 ° . Vẽ Ot là tia phân giác của góc yOz.

a) Tính số đo góc yOz và yOt.

b) Tính số đo góc xOt.

* Mark the letter A, B, C, or D on your answer sheet to indicate the sentence that is closest in meaning to each of the following questions.

Though he tried hard, he didn’t succeed.

A. However he tried hard, he didn’t succeed.

B. However hard he tried, he didn’t succeed.

C. However he didn’t succeed hard, he tried hard.

D. However he tried hard, but he didn’t succeed.