为什么产气正常，炉具完好，但火力不足？
参考答案：沼气炉具混合空气不足。
--- Does Mary work carefully?
---Yes. I think she works __________ in our class.
A．much carefully
B．more carefully
C．most carefully
D．much more carefully
无牙畸形常伴随（）
A.毛发稀疏
B.指甲缺失
C.缺少皮脂腺
D.汗腺少
E.以上都有
