除去FeCl3溶液中的Fe(OH)3胶体,可行的方法是( )
A.过滤
B.蒸发
C.加入适量的盐酸
D.加入适量的NaOH溶液
答案:C
Susan’s parents bought a large house with a swimming pool. It ______be very expensive.
A.can
B.must
C.mustn’t
D.can’t
被困在室内应如何保护自己?