临床上,根据病变进展和严重程度,将慢性高血压性视网膜病变分为_______、______、______、________四级。
参考答案:I级;Ⅱ级;Ⅲ级;Ⅳ级
You used to be really little fat, _______ you? [ ]
A. did
B. Didn't
C. didn't
D. Did
油船污染海洋的主要原因,哪一项排油量大?()
A.压载水.洗舱水的排放
B.装卸货油溢油
C.碰撞和搁浅而产生货油外溢
D.加油操作失误