many people find sports cars desirable.desirable这个形容词为啥放在car

这里的desirable 是做宾语sports cars的补足语的,所以放在了它的后面.
find的用法很广泛,可以用多种词类做其宾语的不足语.
find+宾语（名词或代词）+形容词.如楼主的句子.
find+宾语（名词或代词）+名词,如I find Beijing a good place.
find+宾语（名词或代词）+现在分词.如I found John singing in the next room when I passed by.
find+宾语（名词或代词）+过去分词.如I found me lost.
find +宾语（名词或代词）+介词短语.如;I found the stone bridge over the big river.

这是形容词作宾补 当然应该放在宾语后面

find sb. /sth. +adj. 有这个说法，形容词作宾补
比如find it hard to learn English
find the table broken等等

find + sth./sb.+ adj.
发现某人某物怎么样