下列物质易溶于水的是 ____ ,易溶于CCl4的是 ____ (均填序号).
①NH3 ②CH4 ③ ④HCl ⑤C2H4 ⑥Br2 ⑦HNO3 ⑧SO2.
计算:﹣2+4=____ .
—_______ do you go to school?
—By school bus.