Spring in my town.

I love spring. It is a wonderful season. The city is changing!
Spring comes and nature awakens from its winter sleep. The days become longer and the nights become shorter. The ground is covered with fresh green grass and the first spring flowers. How lovely the white snowdrops are! There are new leaves and blossoms on the trees.
The birds begin to sing and build their nests. The air is fresh and the sun shines brightly. The days are warm and everything is full of life and joy. Everybody in our town feels younger and stronger. Many people like spring more than other seasons. It is very pleasant to watch how the nature awakens from the its winter sleep. In the spring we can go to the country and have a walk in the woods or by the river, play ball-games, or lie in the sun. Navigation begins on the Neva, start walking ships ? How can a ship walk? . Spring is very beautiful in St Peterburg.

Well done! Very few errors indeed! Highlighted in yellow and crossed out to be removed, red to be added. That which is highlighted in blue I can not understand. Bravo! Молодец!