1.what size of spinner should i use with an airscrew prop 9x4.how's 2 inch dubro?
2.the wing(one piece builded with balsa not foam) of my trainer is twisted on the right-front side,the maximum misaligment is almost 2 cm more ,compared to the left side.
is there anything i can do to correct it.

sorry for my english

Your spinner should match the nose of your airplane unless the engine is totally open, then use whatever looks good as long as it doesn't cover too much prop. You may have to carve out the openings some so it will fit over your prop. As to the warped wing, I assume since you said it was built up balsa it's covered with a heat shrink material. Just twist the wing opposite the warp a little bit past straight (a helper makes this easier!). You'll notice the covering wrinkles when you do this. Holding the wing with the induced opposite twist, simply shrink the covering where it's wrinkled. If it's not right on, adjust it by continuing the same process. You can use either a heat gun or an iron on it. Good luck!

thanks crosswind for the reply and the info - tips.I will try the tip for the wing as sooner as posible.

the tip for the wing really worked crosswind ,so thanks again

Glad it fixed you up! You're most welcome.