Have you heard the story of “The Merchant of Venice” —No. When and where does the story ______ ?

填入下面一段文字横线处的语句，最恰当的一句是倏忽间，林木疏朗处突然闪过一泓澄澈，溪床细沙乱石，纤尘不染，水底的树叶纹脉，清晰可辨，那汩汩的水声好像响在别处。风过树林，树叶哗哗作响，茂密的枝叶丛里又显出一汪清泉，     ，奔突的水声也愈发大了。

No matter how________, it is not necessarily lifeless.

_______ difficult the task may be, we must finish it on time, because we can’t meet such a precious opportunity _______ we have expected.

How long can I keep the book? —A weekYou _____to return it by Monday