He _____ his first wife soon after his graduation from university but _____ a month later. [ ]

He is a successful businessman and he ___ his success more to luck than to ability.

Only in this way ______to make improvement in the operating system. [ ]

etter _________ when he is thinking, as heprefers to solve problems on his own.

下列各句中，没有语病的一句是（ ）