he noticed at once that discipline was slack,为什么discipline不加定冠词?

he noticed at once that discipline was slack,为什么discipline不加定冠词? he was up at once He wouldn’t have been saved even if he ____ to hospital at once. ___professor as he was,he couldn' t work out the problem at once.用什么冠词 1.He noticed that a car was coming twards him(改为同义句） He noticed a car __　＿　him2.Although he is very old,but he still works hard.(同义句） He is very old,___ he __ woking hard 3.we made up our mind to go back home at once (同义 He was fired at once.at once怎么翻译? He wouldn’t have been saved even if he___________(send) to hospital at once. He can't speak much English(同义句)he is going to school at once（同义句） he once studied at one of the most famous universities( )he doesn't want identified为什么是which不是where Why didn't you give the wallet to the man at once He---(disappear)before I realized it was his. he was noticed _____(break)into the shop at ten last night Once he d___,he couldn't change his mind Bob comes out of the station and at once he doesn't know where to go.意思This is the fist time he comes to this town. At last,he noticed his friends were both out of sight.同义句转换At last,he noticed his friends were both out of sight.At last,he saw（ ）（）his friend at once at once 2道英语同义句转换He should hand in his homework now 改为同义句He________________in his homework now.The students needn't hand in their homework at once (改为统一局)The students_______________________hand in their homework at once He gave me a smile when he p_____ by me and noticed that I was looking at him.