Large quantities of water, as well as some other timely help

C

考查时态语态和主谓一致。当主语后面接由as well as, as much as, accompanied by, including, in addition to, more than, no less than, rather than, together with等引导的词组时，其谓语动词的形式要依主语的单复数而定，而quantities of无论修饰可数名词还是不可数名词，谓语动词都用复数，故排除A和D，又因为时间状语是shince引导的，故主句应用现在完成时。故答案为C.