Отсуствие артикля обозначается "no"

He boasted of sailing to Easter Island in his early thirties.
Once a friend of mine is in need I am always ready to give him a helping hand.
Mark is a good worker who can do great deal of our daily work.
At first sight she was not willing to help him.
The scientist suggested setting up several observation points in Pacific Ocean to monitor the process.
Do you happen to know where Alps are situated?
Most exhibits at our art festival are free of charge.
He failed to book tickets for our tour along Nile.
You are asked to visit only reliable sites while surfing Internet.
All preparations have been made to ensure that our voyage around Mediterranean Sea will be successful.
You ought to try harder if you want to make good impression on me.
I was not able to keep in touch with my school friends.
You should be more active than just giving helpful advice.
Could you show me Orange River on the world map?
I wish I had started preparing for the event in advance.
She insisted on the importance of studying a few islands in Atlantic Ocean.
I thing we should exclude Galapagos Islands from our itinerary.
Since you don't want to make use of the resources available you are likely to face difficulties.
We plan to pay a visit to a camp site near St Lawrence river and spend a week there.
Why do you want to make your way to Lake Victoria?
She asked if I had made appointment with them?
I would rather you hadn't gone to Lake Como the previous year.
If I were you I would study sea animals of Indian Ocean.
At that precise moment they were flying over Andes.
From time to time we have something done by other people which we usually call good luck.
Some students want to go to United States and gain some practical experience.
This is the third time I have visited Corsica.
The gardens are open to public during summer months.
In fact he was generally an openhearted person though he was moody one day or another.
At present your efficiency is higher than that of your counterparts.