My suggestion is that we try for a second time.
你what要加哪里啊为什么不能把that换成what？句子缺表语啊但是意思不符合啊，My suggestion is what we try for a second time.先把for a second time去掉，句子的意思就成了我的建议是我们所尝试的。My suggegestion is that+句子