Tao Wu asks:
Would you let me know the usage of "till" and "until"; what is the difference between them?
My dictionary sees no difference. For "till," it gives the following:
1. to the time of; up to; until. He slept till noon.
2. before: with the negative. I can't go till noon.
1. up to such time as; until. Till death do us part.
2. before: with the negative. They couldn't go till he came.
For "until," the definitions are the same. The origin is the Old English word "til," meaning "to." "Until takes an Old English prefix, "un," meaning up to, as far as.