以原发性DNA损伤为检测终点的致突变试验是（）

A.UDS试验

B.Ames试验

C.基因正向突变试验

D.微核试验

E.染色体畸变试验

—How was your summer holiday, Peter?

—We had ____ in Beijing.[ ]

A. quite a good time                  

B. a quite good time

C. very a good time                    

D. very good time