一道很难的高中英语单选题--------------务必高手帮忙
28、Themanintheleadswunghisrightarm _____ asignalforustostop.
A:asiftomake B:eveniftomake C:asthoughmaking D:eventhoughmaking
1、请选出答案并解释原因;
2、请帮忙标准翻译.