Butterflies ________ a sweet liquid produced by flowers, which bees and other insects collect.

Now that the forest was destroyed by a big fire, a large ________of trees ______ to be planted on the mountain．

After the snowstorm broke out, what should be immediately done is to provide ________ for those people who lost their homes.

(2013·石家庄高三一模)Overuse of computers will ________ to the failure of our      eyesight, which is a warning to us all.

You can’t see things clearly through a telescope unless it is _____ correctly to your sight.