--Tom said their teacher speaks too quickly for him and Betty to understand.

--________ Mary and Bob said they could understand him.

A．Forget it!

B．Think nothing of it!

C．Really?

D．Never mind.

不属于恶性黑素瘤中瘤细胞形态表现为

A．多边形

B．梭形

C．空泡形

D．泡沫状

E．树枝状