1. Why do Watergate culprits keep collective silence?
    为什么水门事件的罪犯们全都保持沉默?

2. Her basket on her arm, she went to the fruiterer´s, the grocer´s, the butcher´s, bargaining, defending every sou of her miserable money.
    胳膊上挎着篮子，她去水果店、杂货店和肉店，讨价还价，极力维护辛苦挣来的每一个铜板。

3. However, the collective smoke from thousands of factories, over the past two centuries, has caused enormous increases in air pollution levels worldwide.
    但是，在过去的两个世纪中，从千万家工厂排放出的烟尘已大大加剧了全球大气的污染度。

4. Many of the tourists on board had begun bargaining with the tradesmen,
    船上许多游客开始同商贩讨价还价起来，