"对议员等游说活动" can be translated into English as "lobbying activities targeting parliamentarians and the like" or "lobbying efforts directed at parliamentarians and similar figures".
Here, "lobbying" refers to the act of attempting to influence decisions made by officials in the government, especially legislators. "Parliamentarians" specifically denotes members of a parliament or legislative body. The phrase "and the like" or "and similar figures" is used to include other relevant officials or individuals who might be targets of such lobbying activities.