這道題的答案應(yīng)是 the。屬于 It is the first (second, third...) that...句式（從句通常用現(xiàn)在完成時(shí)），意思是“第一（二、三……）次做某事”。這類句式都用the，不用a。又如：　　

This is the first time that I’ve heard her sing. 這是我頭一次聽她唱歌。　　

It is only the second time he has been in a canoe. 這才是他第二次乘獨(dú)木舟。　　

It is the third time that he has waltzed off with the coveted award. 這是他第三次輕易贏得那個(gè)令人垂涎的獎勵(lì)。　　

I love this film. I think it’s the fourth time I’ve seen it. 我喜歡這部電影，我想這已是我第四次看這部電影了。　　

值得注意的是，涉及 time 的類似表達(dá)有點(diǎn)特殊，因?yàn)橛袝r(shí)用 the 和用 a 意思沒什么區(qū)別。如：　　

He married for a second time. 他結(jié)了第二次婚。（摘自新牛津）　　

The camcorder failed for the third time. 攝像機(jī)第三次出故障。（摘自新牛津）