Task 4. Choose the proper form of the verb. 1. The mathematical tables of the 19th century full of mistakes.
a) were b) was c) will have d) had
2. He the machine the Difference Engine because it worked by solving what mathematicians call “difference equations”.
a) will call b) call c) called d) calls
3. Data input devices since the sixties as a graphic user interface.
a) is used b) are used c) will have used d) would used
4. A trackball a stationary device to the mouse.
a) is related b) has related c) have been related d) will related
5. The cursor in the direction your finger moves on the pad.
a) will moves b) moved c) moves d) have moving
6. The enter key often to cancel data entries and to terminate the execution of commands and programs.
a) will been use b) is used c) was used d) are use