该公司声称自己对污染没有责任。

The company ___claims it is not responsible for the pollution.

他声称见过总统，但我不相信他。

He ___claims to have met the President, but I don't believe him.

一个未知的恐怖组织声称对这次袭击负责。

An unknown terrorist group ___has ___claimed responsibility for the attack.