Fill in the gaps in the sentences using the appropriate verb forms.

1. Welcome to Vitebsk. I hope that you **are enjoying** your walk around the city. 2. Now we **are** in the centre of the city. It **lies** on the Zapadnaya Dvina River. 3. We just **crossed** the bridge across the river. 4. Now **we are going to visit** the main sights of Vitebsk.