①干冰﹣人工降雨
②Na2CO3﹣制玻璃
③Fe2O3﹣红色油漆或涂料
④Al2O3﹣耐火材料
⑤NaClO﹣消毒剂
⑥NaCl﹣制纯碱;
⑦KAl (SO4 )2﹣消毒、净水.
A:3
B:4
C:5
D:6
Robert Hunt sometimes advises the students common problems.
Peter's father often watches basketball games __________ TV.