正常人潮气容积为500ml,其中死腔气有()
A.100ml
B.125ml
C.150ml
D.50ml
E.250ml
参考答案:C
---Would you like some ________? ---Yes, please. Fruit is good for health.
A.apples
B.eggs
C.potatoes
D.coffee
西周时“一人跖(踏)耒而耕,不过十亩”;战国时“一夫挟五口,治田百亩”。引起这一变化的根原因是
A.公田变为私田
B.铁犁牛耕的推广
C.国家走向统一
D.封建制度的确立