宾语从句的时态 当主句为一般现在时,现在进行时,一般将来时,从句要跟什么时态 如果主句是现在完成时呢

宾语从句的时态是这样规定的：主句为过去式,从句需用过去时的某种形式,如一般过去时,过去进行时,过去将来时等（真理、客观事实除外）；主句为现在时,从句可根据需要用所需时态。We all know that he has studied English since 1998。We believed that he had earned enough money to build a house。The teacher told us that the sun rises in the east。