A:酸能使紫色石蕊试剂变红,紫色石蕊试液中通入CO2后变红,故CO2是酸
B:酸性溶液的pH小于7,食醋呈酸性,故食醋的pH小于7
C:在同一化合物中,金属元素显正价,故非金属元素一定显负价
D:将蔗糖研碎后能加快它在水中的溶解速度,说明颗粒的大小也会影响蔗糖的溶解度.
历史课上,小敏和肖钢对于官渡之战的性质产生了疑问,请你帮他们从下面结论中,选出正确的一项( )
It's a fine day today. The children are playing with their toys.
Amy has a new plastic cup. It's red. Mike has a new toy truck. It's purple and green. Sarah has a lollipop. It's orange. John has a new bucket. It's green. Bob has a yellow balloon, it's nice.
Mike and Bob are sharing their toys with others. How happy they are!
根据短文内容,判断正误。
祸患常积于忽微,____。
下列事件直接促成马克思主义在中国广泛传播的是 ( )