Определите в них видовременные формы глаголов и укажите их инфитив in few days we will send you our samples by separate mail. our raw materials are in great demand on the world market. the chief manager has not studied the latest catalogues and pricelists yet.

In few days we will send (Future Simple Tense; inf - to send) you our samples by separate mail.
Our raw materials are (Present Simple Tense; inf - to be) in great demand on the world market.
The Chief Manager has not studied (Present Perfect Tense; inf - to study) the latest catalogues and pricelists yet.