After Tim finished his homework,he could play computer games.保持句意不变：Tim ___ play comuter games ___ he finished his homework.Tim could play computer games when he finished his homework.这样是否正确
问题描述：
After Tim finished his homework,he could play computer games.
保持句意不变：
Tim ___ play comuter games ___ he finished his homework.
Tim could play computer games when he finished his homework.这样是否正确
答
couldn't ,until