do all pro tennis players hit....?

Yes Kina. Every player in the world hits the ball flat: WHEN THEY CAN.. Tennis, like golf or chess requires that you adapt your technique to fit the situation. There have always been players who hit a ball with less spin than the average, but these players are going the way of the dodo as its not strategically intelligent tennis to give yourself so little margin for error for most shots in a rally. The most successful players who did this most often were borg, conners, graf and of course mcenroe. In more recent times the best flat baller has to be federer along with most of the top russian women. But the ball is only flattened out when they are returning a high bouncing ball which they can attack and end the point with. The best american examples are roddick and blake, but they don't do it as well, as they are not usually patient enough to wait for the 'right' ball to flatten out and end up catching tape. The real reason behind this fact is equipment; the larger and softer faced frames of today allow for more topspin which is a good thing because if they didnt, you'd be hard pressed to keep the ball in the court on a normal, solid ground stroke. The older frames had much less spin effect mechanically with smaller heads, flexible throats and harder faces (the sting bed) and sting itself. To 'not' hit flat was the challenge and imparting topspin was actually quite more difficult. Now, for the better, frames can be swung much more naturally and generate huge amounts of topspin almost all by themselves. But to be successful, you need to have as many shots in your arsenal as you can master - and the 'flat kill shot' still has a very strong presence in the game today.

If you can use both topspin and a hard flat hit it is to your advantage as well as slice.

All professional tennis players are able to use all of these and will break up their game accordingly, so that their opposition does not know what kind of shot is coming next.

Not all, on occasions, all players hit flat. But none that actually consider a flat shot, the one they hit all the time. John McEnroe hit flat, but yeah that was a pretty long time ago. I think topspin is much better, because it doesn't take much more effort or skill to learn it, and hit it as much as you can, and its more of a challenge for the other player to hit back.

All tennis players hit topspin except sometimes when they are going for a winner and they want the shot to go faster, so they don't hit topspin.

I wouldn't say ALL professional tennis players hit with topspin, but I'm sure most do. With topspin, it's easier to hit it low (and in the court, for that matter) and it's harder for the other person to hit it back.

nobody hits flat anymore. the last one to do so was Great Pete , but he mostly had topspin as well. there's no better of the two , topspin is hard to adjust to , and flat is hard to get to. hitting flat is very difficult , topspin is the natural swing on the ball. but you havve to be really fast on the court if you play a lot of topspin ( Michael Chang , Agassi , and Nadal ).

is this Sharapova , can i take a picture ?

its better to have topspin because its harder for you apponent to return the ball

umm i think novak dosent!!!!