关于回声强度的描述,不正确的是()
A.皮下脂肪组织为低回声
B.肾皮质为等回声
C.均质的固体可呈无回声
D.正常软骨为高回声
E.血液中混有微气泡时可引起回声增强
参考答案:D
___I don't think he is studying English in his room now.
____Oh, _________?
A.does he
B.doesn't he
C.is he
D.isn't he
厨房炉灶排烟罩的滤油网的清洁周期是()一次。
A.每年
B.每季
C.每月
D.每周