写出下列物质的化学式:水____________;氧化镁____________;碳酸__________;五氧化二磷_____________;氨气_____________;二氧化硫_______________。 答案:H2O MgO H2CO3 P2O5 NH3 SO2看图,选择填空
--Can you fly a kite, Jim?
--Yes! It is _____.
--Oh, no! It is _____.
A. hard;happy B.easy;hard C. happy;hard