新东方夏令营介绍在英语学习中语法的知识—被动语态。

    新东方夏令营介绍，被动语态是相对主动语态而言，表示被动的句式，其基本结构为：be + 动词过去分词

    第一节 与主动态的显著区别
 
    被动语态与主动语态在形式上的特征是选择使用哪一种语态的必备常识，也是解题的法宝。

    1. 被动语态中谓语动词必须是及物动词

    2. 被动语态中谓语动词之后绝大多数不能再接宾语只有少数可接双宾语的动词，如：consider, give, call, name等，例如：she was considered a genius in painting.

    he was called a hero.

    the ship was named queen elizabeth.

    改错题中，若在被动句里, 动词(上面提到的接双宾语的动词除外)的被动式之后出现宾语，则此处必有错误，可改为主动句；同样，在主动句中, 若及物动词后没有宾语，也必定有误，可改为被动句

    3. by可视为被动语态的标志词，by之后的名词短语是句中动作的施动者；在题干中若见到by+名词的结构要优先考虑用被动式如: the wall is painted by tom.

    the book was written by mark twain.

    注意1：by之后如果接的是动名词，则表示方式、手段，不能视为被动式的标志，且此时谓语应用主动式，如：he passed the exam by cheating.

    注意2：对于know来讲，一般用be known to 而不用be know by例题：

    (1)the seating of musicians in an orchestra is arranged ----to produce the desired blend of sounds from the various musical sections.

    (a) the conductor of(b) from the conductor(c) the conductor and(d) by the conductor答案：d解释：若不要空白处的话, 此句亦很完整, 可清楚的看出空后的不定式短语表目的, 那末可能填入的是arrange的施动者, 自然应该用by来引导；a of不能接不定式; c 不能在被动式后面接宾语

     第二节 被动语态的不同时态

     被动语态由助动词be加过去分词构成，它也会有不同的时态，其时态主要通过助动词be来表现。其中对过去进行时的表示方法需留意如：the potatoes are being peeled in the machine.

    she was being questioned by the police.

    其它时态举例：

    the table has just been cleaned. （现在完成时）his passport had been changed without his notice. （过去完成时）the press conference will be held in three weeks.  （一般将来时）例题：

    (1)experiments in the photography of moving objects ----in both the united states and europe well before 1900.

    (a) have been conducting(b) were conducting(c) had been conducted(d) being conducted

    答案：c

    解释：此句缺少谓语, conduct是及物动词, 后若无宾语应是被动式, a b 首先被排除, d分词不能单独作谓语