Don’t be angry with the boy. He made the mistake ______.
| A．on purpose | B．by accident | C．in surprise | D．at once |
_______ you begin the work , you must carry it out through to the end.
| A．When | B．Though | C．Sometimes | D．Once |
I’ll start early , _______ it is dark or light .
A. howeverC. whether C. if D. though
He is so strongly built that he looks _______ he could lift an elephant.
| A．if | B．as if | C．like | D．that |
I’ll let you know ____ he comes back.
| A．before | B．because |
| C．as soon as | D．although |
She will sing a song ____ she is asked.
| A．if | B．unless | C．for | D．since |