1.thought about 后面賓語(yǔ)是 that experience;
2.have actually joked about how naïve I was 意思是：對(duì)我的天真感到好笑；
3.have actually joked about how naïve （這個(gè)地方不應(yīng)該有that）
4.幫你分析一下：整個(gè)句子是一個(gè)并列復(fù)合句：并列句的第一半是I have thought about that experience several times （注意這里的that并非引導(dǎo)賓語(yǔ)從句的引導(dǎo)詞that,而是指示代詞that,意思是“這個(gè),那個(gè)”.
第二半是 and (I) have actually joked about how naïve I was.這里how naive I was 是賓語(yǔ)從句；而這個(gè)賓語(yǔ)從句中I是主語(yǔ),was系動(dòng)詞,naive表語(yǔ),how狀語(yǔ)修飾naive.
5.翻譯一下：
那個(gè)經(jīng)歷我曾經(jīng)想過(guò)了好幾回,我也對(duì)我的天真感到可笑.