Present tenses

How many tenses are there?

Many birds of Europe ... South to Africa in winter.

The weather ... very cold in Moscow in the winter.

Don't forget to take your umbrella. It ... outside.

Justin ... a book about his adventure in Tibet. I hope he can find a good publisher when he is finished.

I ... them three times, but I still haven't received a reply.

We ... three major snowstorms so far this winter. I wonder how many more we will have.

We ... four tests so far this week. We require a great and long holiday!

It's ten p.m. I ... for three hours and probably won't finish until midnight.

She ... to several specialists about her problem, but nobody knows why she is sick.

The telephone ... for almost a minute. Why doesn't someone answer it?