Put the necessary article(a, he cant .if he goes ,hell river in the world ocean in the world is pacific the founder gallery was ivan tryakov i want to show square forests and oceans are parts the most famous moscow theatre is theatre

He can't speak German. If he goes to Germany, he'll need a translator.
The longest river in the world is the Nile.
The largest ocean in the world is the Pacific Ocean.
The founder of the Tretyakov Gallery was Ivan Tryakov.
I want to show you Red Square and the Kremlin
Forests and oceans are parts of the environment.
The most famous Moscow theatre is the Bolshoi Theatre