OK, then let's explain. "Pending" and "Under Contract" are the essentially same thing. The property in question now has a buyer who has completed the bargaining process and has signed a Purchase Contract agreeing to buy the property under the terms and conditions of the contract. Here's where this sometimes gets interesting. Common terms and conditions could include having to sell something the buyer owns, the need to secure a mortgage in order to buy, or perhaps the contract is subject to certain inspections. Any of these things could cause the contract to fall through and the property to come back on the market at some point, so do not make an automatic assumption that you'll never get a chance to get it. S*** happens. We don't see it as often as our competition, but we are certainly not immune.
In some cases, "Pending" may be used if bargaining is going on but a contract has not yet been signed, thereby binding the seller and buyer together. We don't use it this way on this site, but some other firms might. In a case such as this, an offer could be submitted and and accepted while the original party was still bargaining, thereby leaving him out in mid-air, wondering, "What happened?"
But if you see "Pending" or "Under Contract" here, all you can do is to wait and see if it sells. Don't like waiting and doing nothing? Then you can submit a "back-up offer", which, if the owner accepts, catapults you into first position if and when the original contract should fall through. In my experience, most backup offers never get exercised - more would, however, if only they were made. You have to be sure that you want that particular place and are willing to wait in hopes that you can get it, rather than moving on to find a substitute.
"Sold" means just that. You are too late, there is a new owner. All you can do now is to offer him more in hopes that he will take a quick profit and sell it to you. Small chance, but if you want it bad enough, it only hurts your wallet if you try and they accept.