It is difficult for any of us to eat better, exercise more, and sleep enough, ______ we know we should.
| A．because | B．even if |
| C．unless | D．before |
The window is never opened ____ in summer.
| A．but | B．except | C．except for | D．but for |
Nobody knows it ____ me.
| A．except for | B．except that | C．besides | D．but |
I don' t think Xiao Li is ____ the other students ____ mathematics.
| A．after, on | B．after, with | C．behind, in | D．behind, at |
_____ hearing the news, I was wild ____ joy.
| A．At, in | B．On, with | C．After, by | D．/, over |
My father began to work ____ a bus driver when he was twenty years old.
| A．for | B．to | C．at | D．as |