48÷8=____  64+26 =____   8×7 =____   56-35 = ____   24+28 =____ .

9×3 =____  76-34 =____   63÷7 =____   8×8 =____    97-63 =____ .

72÷8 =____   79+15 =____   65-17 = ____  18÷2 =____ 52+48 =____.

7×7 = ____   54÷9 =____  81÷9=____   4×7 =____  70-23 =____ .

选出下列对病句修改有误的一项（    ）

①浓硫酸；②浓氢氧化钠溶液；③饱和氯化钠溶液．