16、世上沒有什么比…更令我高興。
    Nothing in the world can delight me so much as …
    例︰世上沒有什么比到快餐店吃漢堡更令我高興。
    Nothing in the world can delight me so much as having hamburgers in fast-food restaurants.
    17、… 是必要的 It is necessary that S （should）V
    … 是重要的 It is important/essential that S （should）V
    … 是適當(dāng)?shù)?It is proper that S （should）V
    … 是緊急的 It is urgent that S （should）V
    例︰我們當(dāng)保持公共場所清潔是應(yīng)當(dāng)?shù)摹?BR>    It is proper that we （should） keep the public places clean.
    18、每當(dāng)我聽到…，我就忍不住感到興奮。Whenever I hear …，I cannot but feel excited.
    每當(dāng)我做…，我就忍不住感到悲傷。Whenever I do …，I cannot but feel sad.
    每當(dāng)我想到…，我就忍不住感到緊張。Whenever I think of …，I cannot but feel nervous.
    每當(dāng)我遭遇…，我就忍不住感到害怕。Whenever I meet with …，I cannot but feel frightened.
    每當(dāng)我看到… 我就忍不住感到驚訝。Whenever I see …，I cannot but feel surprised.
    例︰每當(dāng)我想到我家附近那一條清澈的小溪，我就忍不住感到悲傷。
    Whenever I think of the clean brook near my home，I cannot but feel sad.
    Every time I think of the clean brook near my home，I cannot help feeling sad.