------- May I use your mobile phone?       --------- _______________

A．why not?

B．OK, enjoy yourself.

C．Go ahead.

D．Yes, but you’d better not.

下列哪一型白血病最常引起中枢神经系统白血病

A．急性淋巴细胞白血病

B．慢性淋巴细胞白血病

C．急性单核细胞白血病

D．急性粒细胞白血病

E．慢性粒细胞白血病