（a+b）×c=______×______+______×______．
（a+b）×c=a×c+b×c；
故答案为：a，c，b，c．
--- Do you know _____ Mr. Black’s address is.
--- He may live at No. 18 or No. 19 of Bridge Street. I'm not sure of _____.
A．what; which
B．where; which
C．where ; what
D．what; where
苏湖教法
