一楼提醒的对，这样的开句有错误，应该是 I've now tried ...I've = I have have + 动词过去分词 使用的是完成时，表达 "已经、曾经" XX 的意思。I've now tried ... 意思指 "我现在已经试过了 ..."例如：I've now tried two different ways to explain to him, but he still doesn't seem to understand.我现在已经试过两种不同方法为他解释了，但他似乎仍然不明白。这样改变后就合乎语法，也能解说清楚了。
