Give the proper tense of the verbs given in brackets.

1. An ordinary business adding machine (to be) a very simple example of a computer. 2. When a computer (to do) reasonable operations, it (to compute) or (to calculate). 3. When l (to come) into the room my friend (to compile) a program. 4. A computer (to store) information which it (to receive). 5. ......... (to come) to the laboratory, I....... (to show) you how to calculate by using a computer. 6. The electronic computer ES -1045 just (to perform) its calculations.