Similar to conditional sentences are those that use "wish" to express something isn't true now, or it wasn't true in the past. To make sentences with "wish" properly, a knowledge of the Sequence of Tenses is important.

I wish I had more money.

(This describes a present situation. In fact, I don't have more money.)

She wishes he would talk to her more often.

(This also describe a present situation. Notice that the modal verb "would" is used here. "Would" and "could" are frequently used in these kinds of sentences.)

They wish they hadn't bought that house.

(This describes a past situation that can't be changed. They regret their decision, but you can't change the past. Notice the use of the past perfect after "wish.")

Yesterday Tom moved his chair and hurt his back. Now he wishes he hadn't done that.

(The verb "do" is especially useful. You can use it for just about any kind of mistake you made in the past.)

Tony wishes he had a job as a radio announcer.

(The verb "have" is often used after "wish." In this situation, he doesn't have this job, but you use the past tense of have: had.

"I wish I knew the answer."

(You don't know the answer, but you wish you did. Again, the past tense is used to describe a present situation.)