He owns a house which is four times as big as his son's.
He can eat three times as many as Tom does.
句法结构：
主语+谓语+ 数词+ as+形容词+as+ 被比较的对象
he owns the house three times bigger than his son's
He can eat three times more than Tom does.
句法结构：
主语+谓语+ 数词+ as+形容词比较级+than+被比较的对象