点是主句动作的启始点，所以主句一般要用完成时态。

［误］ Because he didn't study hard, so he didn't pass the exam.  ［正］ He didn't pass the exam because he didn't study hard.

［析］ because 与 so在英文中两者不能并用的，只能在句中用其一。

［误］ He was such excited that he could not speak.

［正］ He was so excited that he could not speak.

［析］ so与such的用法可以分为四种情况，①用于单数可数名词之前，其格式是such+不定冠词+形容词+单数可数名词，如：It is such a beautiful book that every child likes it. 也可以用so, 其格式是so+形容词+不定冠词+单数可数名词，如：It was so beautiful a book that every child likes it. ②在不可数名词前或可数名词复数前这时只能用such, 如：It is such good weather that we want to swim. 又如：They are such good students that they can pass the exam easily. ③在few, little， much, many 这4个字前只能用so而不能用such, 如：I have so much money that I can buy everything I want. ④当that前只有形容词或副词时，这时只能用so, 如：She is so beautiful that every one likes her. He ran so fast that I couldn't keep up with him.

［误］ He got up earlier this morning so as to that he could catch the first bus.

［正］ He got up earlier this morning so as to catch the first bus. ［正］ He got up so earlier that he could catch the first bus.