预制安装水池在水泥砂浆保护层施工完毕后,应遮盖、保持湿润不少于()。
A.28d
B.7d
C.1d
D.14d
参考答案:D
All my family had breakfast at half past six,_______my neighbourhood.
A,so has B,nor did C,so had D,nor had
当人体长时间大量运动后,血液中的水、无机盐、葡萄糖等营养物质会大量消耗,此时胰岛A细胞和胰岛B细胞会发生怎样的变化()
A.胰岛A细胞活动加强,胰岛B细胞活动减弱
B.胰岛A细胞和胰岛B细胞活动都加强
C.胰岛A细胞和胰岛B细胞活动都减弱
D.胰岛A细胞活动减弱,胰岛B细胞活动加强