mermaid2011

一点想法：
as big as 30 feet long-->WORDY
X is as big as 30 feet-->BETTER
X is 30 feet long-->BETTER
as big as和long都是表示尺寸大小，同样的意思，没有必要同时用，用一个就行了

X is as big as Y. X和Y都是名词时有可比性。如：
The apple is as big as the orange. -->CORRECT(As Serena0710 mentioned)
The apple is as big as the size of the orange.-->INCORRECT
A is as tall as B.-->CORRECT
A is as tall as the height of B.-->INCORRECT