once, twice, three times, five times, seven times, never
play sports
eat fruit
eat vegetables
Sam
____
six times
Judy
four times
Lily
three times
①民族 ②民权 ③民生 ④民主
将稀盐酸分别加入到氢氧化钠溶液和碳酸钠溶液中,如图所示