Read the text and choose the right variants in the sentences below.
Some dolphins live in rivers and some live in the sea. The Yangtze River runs across China from west to east. Baiji dolphins have been living in the waters of the Yangtze River for centuries. They have eyes on top of their heads, but nowadays they cannot see very well because there is nothing to see in the dirty water. The river itself has changed a lot. Now it is full of ships, noise and pollution. The dolphins didn’t change their behaviour after the river became dirty, but their life now is much more dangerous.
Dolphins can usually hear very well, they make their own dolphin noises and in this way they talk to other dolphins. Nowadays there is a lot of other noise in the river, especially the loud noise from big ships. Baiji dolphins often can’t understand these noises and kill themselves swimming to the ships. The Chinese understand that Baiji dolphins are in danger. They began building a home for them in the river.
In India and Bangladesh dolphins are also in danger. The meat of sea dolphins is an important food for people in many countries and humans kill hundreds of thousands of them every year.

1) Baiji dolphins live in ... .
2) The water in the Yangtze River used to be ... .
3) Baiji dolphins cannot see well in the water of the Yangtze River because ... .
4) Baiji dolphins cannot hear well nowadays because ... .
5) Dolphins are in danger ... .
6) The Chinese began building a home for Baiji dolphins ... .