3～6个月胚胎体内最主要的造血场所（）
A.卵黄囊
B.肝脏
C.骨髓
D.脾脏
E.淋巴结
参考答案：B
When a customer withdraws money from the bank, it is required to leave his signature. But how can we be sure it is_______?
A．absolute
B．alternative
C．academic
D．authentic
黄疸以哪几项为主症
A．目黄
B．爪甲黄
C．身黄
D．齿垢黄
E．小便黄
