______we _______the work by next Friday,we won't be able to attend the meeting. A: If ....shall finish B: Unless.....finish C: When...finish D: Once...finish

Multitasking can make us finish all the things at once .

I will be able to help you （）I finish my work A: as B: because C: while D: once

—Need I finish the task at once?—Yes, you ___. / No, you____. A: must; needn’t B: need; mustn’t

同时: all at once|all once|at all once|at once

I’ll go with you as soon as I ______ this letter. A: will finish B: shall finish C: finish

Only in this way ______ on time A: we can finish the task B: finish we the task C: we finish the task D: can we finish the task

The manager ordered the work ______. A: start at once B: to be started at once C: to start at once D: at once started

He ordered the work (). A: started at once B: to be started at once C: to start at once D: at once start

The phrase "once in a blue moon" in last line refers to______. A: all at once B: once for a long time C: once in a while D: once and for all