when he saw it happening,he called the police.这里的为什么用happening?而不用happened呢?

He saw the bag when his bike hit it.() Tom saw us on the beach when heTom saw us _____(lie) on the beach when he passed it. when he saw it happening,he called the police.这里的为什么用happening?而不用happened呢? The man saw it __ when he was walking past.The man saw it __ when he was wacking .A.happen B.happening为什么B不行这几个回答不是多满意:::请专业的给与更合理的解释， He saw the bag when his bike hit it.用not……until……改写句子He saw the bag when his bike hit it.用not……until……改写句子 英语翻译是when he saw me还是when he see me还是when he sees me? he was happy when he saw his mother(同义句 He was ( ) (surprise) when he saw me in the street He gave me a r________ when he saw me He was s_____ when he saw the strange object. 英语翻译1.The movie was OK,but he couldn't enjoy it.2.He got annoyed when he saw a man smoking in the restaurant. The man said he saw a UFO.but when he took out of his camera ( )had disappeardA.that B.it 选哪个为什么? when the foreign tourist saw the Great Wall,he said____! A.what a great wall it isB.how great a wall is it The baby was wery happy when he saw his mother. The boy ran _____ when he saw his mother. He was shopping when I saw.用was shopping提问 he was play tennis when I saw him 改错 the wind stopped ______(cry)when he saw his mother