Look at these sentences.
- Animals cannot survive for long without water.
- So desert animals have to find different ways of coping.
The first sentence says what cannot happen or be done; the second tells us what must, therefore, be done, what it is necessary to do. Complete the sentence using cannot and have to/has to.
We —————————— see bacteria with our eyes; we —————————— look at them through a microscope.
We cannot see bacteria with our eyes; we have to look at them through a microscope.