请根据句意从方框中选择合适的动词，并用其适当时态填空，使句子通顺。
read    chat      not realize     agree    operate
We __________ happily when suddenly someone knocked at the door.
Unless you try your best, you__________ your dream.
I __________ this magazine. Will you please show me another one?
Don’t make any noise while the doctors __________ on the patients.
I asked him if he would help me and at last he __________.