He was _______ the preparation of an international conference when I arrived in Beiji

By the time you get to the office I______all the documents for the meeting.A．was preparing

The most successful treatment described in the passage was a serum prepared from ______.A．

－－－－ If he_____ , he ______ that food.－－－－ Luckily he was sent to the hospital immediately.A．was war

Although he thought he was helping us with the job, he was only ______.A．in a wayB．in the

Today Bob was late again for class because he overslept （睡过头) , but he______an excuse o

He was held in the police station because he ___________ to an offence.A was relatedB co