while he saw his mother ,the boy stopped crying.为啥用while as soon as 那用when

He looked for his sister.He saw a car accident happen.用while连成一句话. while Tom saw the UFO,he was walking down the street with his friends有一处有错, John looked for his sister.He saw a car accident happen.(用while连成一句) John looked for his sister. He saw a car accident happen.用While连成一句怎摸说 While Tom was playing with the balloon,he saw a plane ___ (fly) over his head. while he saw his mother ,the boy stopped crying.为啥用while as soon as 那用when __________the boy saw his mother he burst into tearsA a moment B each time C while D as soon as 摔倒 The man ____ on to his back and rope went into the air.While he was____ on his back,he saw. 同义句 He is going to buy a present for his mother.----- he going to ----- a present ----- his mot he was happy when he saw his mother(同义句 Mot 英语翻译While waiting for a bus to the office where he was supposed to be interviewed,he saw an elderly man wildly kicking the tyre of his car.1、请解释be supposed to 2、请标准翻译这个句子, On his way home he saw Johnson是什么意思 The baby was wery happy when he saw his mother. The boy ran _____ when he saw his mother. He saw his old friend yesterday.(改成一般疑问句) he saw a boy on his way home the wind stopped ______(cry)when he saw his mother