—Do you know_________?

— He has gone to the museum.

A．where he lives

B．where he is

C．how he is getting on

D．what’s wrong with him

以下关于视网膜母细胞瘤的描述，正确的是

A．肿瘤边界较清

B．婴幼儿最常见的眼球内恶性肿瘤

C．为神经内胚层的恶性肿瘤

D．肿瘤很少向颅内生长

E．瘤内钙化是较特征的表现