-It's the second time that I ________ to Shanghai.

-What great changes！It's ten years since I ________ it last time.[ ]

A．have been; left  

B．had been; left

C．am; had left  

D．come; had left

借贷记账法的记账原则是（）。

A．有借必有贷，借贷必相等

B．一借必一贷，借贷必相等

C．一借可多贷，借贷可不等

D．一贷可多借，借贷可不等