He decided to buy the painting------first sight.A at B in C

He decided to buy the painting______first sight.
选 A at
因为at first sight 是第一眼的意思,固定搭配
in one's sight 在某人看来
I seem ____someone koncking at the door
选 to hear
seem 的用法：
it seems that 就是it 做主语,后面跟从句
sb seems to do 就是人做主语,后面跟不定式
副词修饰动词位置可前可后,无所谓
比如
read loudly (后）
the noise is slowly driving me mad（前）
He missed the bus by three minutes
就是他晚了三分钟,没赶上那趟公交车
这里的by 意思就是截止到三分钟为止,相当于大约,模糊一点,理解为for 3 minutes 也行,不去看也行