⑴How many seasons are there in a year?____ A. Four
⑵What about some milk?____ B. She's in the kitchen.
⑶What would you like?____ C. They're on the sofa.
⑷Where are my warm clothes?____ D. Sounds good.
⑸I can't find Mum.____ E. I'd like a hamburger.
将19.45克碳酸钠和氯化钠的固体混合物放置于烧杯(重50克)中,加入一定量的水,固体全部溶解,然后向烧杯中滴加一定溶质质量分数的稀盐酸,实验测得烧杯及杯中物质的总质量与加入稀盐酸的质量关系如图所示.计算:
①所加稀盐酸的溶质质量分数.
②恰好完全反应时所得溶液的溶质质量分数.
如图(甲)所示,足够长的木板B静置于光滑水平面上,其上放置小滑块A.木板B受到随时间t变化的水平拉力F作用时,木板B的加速度a与拉力F关系图象如图(乙)所示,则小滑块A的质量为( )
216个518是111888.
下列运算中,正确的是( )