You are looking out of the window again .

选C
surprised at
frightened by
anxious about
interested in
我又查了查frightened的用法
1.frightened
【课文原句】You can imagine how I blushed and how frightened I was.(Page 56)
frightened为形容词,意为“恐惧的；害怕的；受惊的”,通常作定语和表语.后可接of sth./ doing sth.,也可接不定式或从句.例如：
Frightened children were crying for their mothers.
They are frightened of losing their jobs.
The little girl was frightened that her mother wouldn’t come back.
【拓展】frighten为动词,意为“使感到恐惧；使惊吓”.frighten sb.into / out of doing sth.意为“吓得某人做 / 不敢做某事”.例如：
The child was frightened by the sudden thunder.
News of the robberies frightened many people into fitting new locks to their doors.
frightening意为“引起恐惧的；可怕的”.例如：
I have seen a very frightening film.
It’s frightening to think of the horrors of nuclear war.
我觉得没有be frightened about
答案错了吧

C
只有anxious能与about搭配

c.