Congressional committees also have the power to cite for contempt of Congress witnesses who refuse to tesify.也可以改为 :
Congressional committees also have the power to cite witnesses who refuse to tesify for contempt of Congress. 如此一来, 意思就不清了 ( to tesify for contempt of Congress ? )
Congressional committees also have the power to cite witnesses who refuse to tesify, for contempt of Congress. 如加一个逗点也可以, 但怪怪的.