The old man is very weak. He walks very slowly lest ____ (Complete the sentence with suitable clause/phrase)

There was a little rain yesterday. If it had rained heavily, we could have gone out. (3rd conditional)

Though junk foods look appetizing they are harmful. We should avoid them.

Opportunity does not always come. You would have succeeded in life provided that you had worked hard. (3rd conditional)

The amount of waste is growing rapidly all over the world and polluting the environment. It is high time we stopped throwing waste here and there. (Past Indefinite) / to stop throwing waste here and there. (Infinitive)

I wish I  I were a poet would express my feelings in my poems.
 

English is an international language. We need to learn it as it is used all over the world.