Before ______ from the ion rocket, the positive

ion beam must be neutralized.

The purpose of the device is ______

 the

process.

Boron is used ______ solid propellants for

rockets.

Match the two parts of the sentence:

_____ pressure is absolutely necessary in this

experiment.

For ______ electrical energy into mechanical

energy, we use a special machine.

Match the words to make a phrase.

Leaving the earth means _______ upwards against

gravity.

Translate into Ukrainian:

be engaged in