Of course! As long as it doesn't hit the net and then go over, it's fine.
If by what you mean is are you allowed to hit the return before it bounces - NO.
Let's are extremely rare in table tennis and you really shouldn't worry about it But just for the beneficial feeling of helping somebody I'm pretty sure there are infanite Just like tennis>
Yes... each time the ball hits the net, on serve, and hits the other side, it is a let.
Almost all of your joints are used in tennis, but the main ones in a tennis serve are the knee joints, and elbow joints.
You can hit an underhand serve in tennis; however, the overhand serve is more effective because it is more powerful. That is why you don't see the underhand serve used much.
Badly.
a serve
A tennis ball!
a tennis ball
A tennis ball.
A TENNIS BALL.
a serve