Ex.13 Translate the sentences.

but — но; только, лишь; кроме

but for — если бы не

1. The proton and neutron have almost the same weight, but the electron weighs only l/2,000th as much as a proton or neutron.

2. The nucleus of hydrogen contains but one proton.

3. An electric current is but a procession of charges.

4. Whether other substances but uranium possessed the property of emitting radiations was of great interest to scientists.

5. It seems that the electron is nothing but a charged particle.

6. But for the atmosphere no life would be possible on the Earth.