B1 Use of English Test 4
B1 Use of English Test 4
B1 Use of English Test 4
Clever birds
The wild birds known as ravens are thought to be very clever. In fact, they can solve
some quite (1)…………….. problems, especially when they’re trying to get food. For
example, one bird was filmed taking a box of nuts from a bird table and (2)
…………….. it onto the ground, so that it would break and the bird could eat the nuts
inside!
Scientists also (3)…………….. that the birds could actually use stones as tools to (4)
…………….. out simple tasks. So in an experiment, they taught five birds to use a tool
to open a box with food inside. The birds soon became very (5)…………….. at doing
this. So for the next experiment, the birds were given a small (6)…………….. of tools
to choose from. They always picked the tool that scientists had given them for the
first task. And hours later, they could still remember which tool they’d used!