they could have come to your help,but they_____in a traffic jam A had been caught b should catch

c were caught d caught 哪个啊？要详细的解释的！

如果我是你;could/：这是一个虚拟语气，表示对现在事实的虚拟表示与过去事实相反的情况 结构为，我就会借给你些：主语+过去时+其他+主语+should/：地球上既有空气也有水) 4： 1. 如果我带钱了;would/：我不可能是你） 2, there would be no living things on the earth;might+do+其他 例.If I were you：没带钱） 5.If he studied harder. 如果没有水和空气。（事实.If I had any money with me, I could lend you some, I would take an umbrella，我会带把伞，我就会告诉你。（事实：不知道） 3。（事实：没有努力 虚拟语气是很重要的一个语法，希望能帮到你 翻译.If I knew his telephone number, I would tell you. 如果我知道他的电话号码。（事实.If there were no air or water，地球上就不会有生物。(事实, he might pass the exam.如果他再努力些，就能通过考试了：他们本来应该来帮助你的对不起，是我理解错题意了 选C 解析

were caught

他被交通堵塞了