Once Johnny starts painting a picture, he won't stop until it______.
had been finished
was finished
is finished
will be finished
本题考查时态与语态。句意：一旦约 翰尼开始画一幅画，他不画完是不会停下来的。 not...until.．．引导时间状语从句时，从句不能用将来 时，主句为一般将来时，从句用一般现在时。it指 代picture，与Fmish是被动关系，故应使用被动语 态。故本题选C。