Some insects __________ the color of their surroundings to protect themselves.

After walking on the zigzag path to the mountain top for a few hours, the tourists gathered under trees ________ shade and ________ down to have a rest.

I noticed ___ at those beautiful flowers.

The old man said that the accident _________ careless driving, so a lot of money _________ by the driver.

There is ____ milk left now. I have to go and buy some.