答案：填why,that
即：The reason why he was late for the meeting was that he missed the first bus this morning.
解析：第一個(gè)空是why引導(dǎo)的定語從句,修飾前面的the reason,第二個(gè)空是that引導(dǎo)的表語從句
翻譯：他開會(huì)遲到的原因是今天早晨他錯(cuò)過了頭班車.
有不明白的請(qǐng)繼續(xù)追問,請(qǐng)問有沒有the reason is because/why 的結(jié)構(gòu)的？大家都知道中國(guó)老師教的都是the reason why...is后面一定要接that引導(dǎo)表語從句，但是 參考美國(guó)傳統(tǒng)詞典because詞條的特別說明：Usage Note: A traditional rule holds that the construction "the reason is because" is redundant, and should be avoided in favor of "the reason is that." The usage is well established, however, and can be justified by analogy to constructions such as "His purpose in calling her was so that she would be forewarned of the change in schedule" or "The last time I saw her was when she was leaving for college". All three constructions are somewhat less than graceful, however.可見， is because 的用法已經(jīng)擺脫了語法的束縛，成為既成事實(shí)了。那也就是在語法課中可以使用咯應(yīng)該可以，不過，如果給學(xué)生講課，最好還是遵循我們中國(guó)老師上課的習(xí)慣吧，否則會(huì)引起歧義，呵呵