题干
Tom is the ____ (heavy) boy in his class.
答案(点此获取答案解析）
heaviest
Tom is the ____ (heavy) boy in his class.
为直流电源，
为浸透饱和氯化钠溶液和酚酞试液的滤纸，
为电镀槽．接通电路后发现
后，使c、d两点短路．下列叙述正确的是（ ）