Определите сколько слов входят в сказуемое
1. The properties of the elements of the Periodic System gradate
quite regualarly from the light elements to the heavy ones.
2. It had been comparatively easy to calculate the number of atoms.
3. Not every substance can accelerate any particular process.
4. Their purpose is to slow down rapid chemical reactions.
5. Taken by themselves, they don’t influence the course of the
reaction.