为什么at present不加the而in the past要加呢?是不是因为介词的关系?

为什么at present不加the而in the past要加呢?是不是因为介词的关系? 为什么at home 不加the 而at the race加the? I saw Ann Wearing a green dress at the school meeting.wear为什么要加ing而不加ed? when i'm 4 years old为什么加years old 而at the age of 4不加years old ______Jack was worried seemed obvious to evreyone present at the meeting.为什么填that而不填what? 有关be present at的用法The experts present at the meeting(出席会议的)were from different parts of the world.为什么 present at the meeting前不用加be动词,不是说be present 有关be present at的用法The experts present at the meeting(出席会议的)were from different parts of the world.为什么 present at the meeting前不用加be动词,不是说be present I saw Boys at the cinema 为什么用both the 而不　I saw Boys at the cinema 为什么用both the 而不用the several?单句 选择题 in the present,at the present分别为什么意思?还有：in the present,at present,at the present这三个短语有什么区别?做题时应如何选择呢? 英语the的用法1.i was at church on sunday.2.i was at the office on monday.3.my son was at school on tuesday.4.she was at the grocer's on wednesday.为什么有的地点前面加THE而有的不加?请说明用法谢谢! i want to take a present for my cousin.为什么不加am I came the same day as she left 为什么不加at啊 at the present at the present 为什么I can go swimming (swim)加ing而I can see the flowers不加(ing) at school at the pool 为什么一个加the 一个不加? at the office还是at office?为什么at church不加冠词the? at present 与 for the present 区别