It is rather that we still do not know how many species there are in the world today.

28The farm as well as its neighboring hills we once spent so much time ____ on a new look as recently as last year

Look at the famous painting __________ Picasso. It’s excellent.

If you keep working like this, you health will ______ under the pressure of work.

Once new difficulties _________ in your work, it’s always important to use your brains