This is ________ useful book. Let's buy it.
A:a
B:an
C:any
D:/
①社会主义建设缺乏经验 ②对国情没有认识清楚
③苏联撕毁合同 ④急于求成
– The East Lake is not far from the Yellow Crane Tower, so you can easily visit _________ in a day. – Fantastic! I can't wait for it.
A、B两烧杯中均盛有100克水,分别加入不同质量的同种固体物质甲,用玻璃棒搅拌使其充分溶解,现象如图所示.此时,B 烧杯中的溶液一定是该温度下的____(填“饱和溶液”或“不饱和溶液”),若要将B烧杯中的剩余固体全部溶解,最好的方法是____。