52.key to solve

[notletrest]

The key to solving the problem is to meet the demand made by the customers.In my eyes the key to solve... is also correct?You see?thanks!

[Tdol]

I prefer solving, but I think solve is also OK.

[notletrest]

After the expiration of (the) three years from the date of the grant of the patent right, any entity may, in accordance with the provisions of Article 48 of the Patent Law, request the Patent Administration Department under the State Council to grant a compulsory license.

I beg your pardon!What do you mean by the above?Thanks!