which 用法 North Korea announced Thursday that it will launch its newest rocket,which many outside the country suspect is a long-range missile that can hit the U.S.mainland,sometime from April 4 to 8,giving other countries three weeks to decide whether to shoot it down or deal with the trouble in another way.中的which many outside the country suspect is a long-range missile that can hit the U.S.mainland,单看这个句子中的which many outside the country suspect 好像是作主

which 用法
North Korea announced Thursday that it will launch its newest rocket,which many outside the country suspect is a long-range missile that can hit the U.S.mainland,sometime from April 4 to 8,giving other countries three weeks to decide whether to shoot it down or deal with the trouble in another way.
中的
which many outside the country suspect is a long-range missile that can hit the U.S.mainland,
单看这个句子中的which many outside the country suspect 好像是作主语从句
而语法上没有查到which加一个句子作主语的用法这里怎么解释?
我就是想问{which many outside the country suspect is a long-range missile that can hit the U.S.mainland,} 这个定语从句再进一步划分句子成分怎么划？