Exercise 1. Choose the proper Russian equivalents of modal verbs.

1) One can assume this to be self-evident. 2) One can expect the scope of research to expand steadily. 3) One can watch more and more people move into biology from other areas of research. 4) One can hardly tolerate one's ideas being criticized, without an attempt to defend them. 5) One can hardly expect a true scien­tist to keep within the limits of one narrow long-established field. 6) One should always keep an open mind receptive to new ideas, so one should not completely oppose speculation, but one must take care not to get too involved in it. 7) One should start a new subject of research with collecting experimental evidence and classifying it. 8) One should be able to pick out the most important things from the great wealth of information. 9) To be a successful scientist one must at the very least be able to ask questions. 10) One has to test the validity of a theory by expe­riments. 11) One need not solve a great many problems to be a great scientist. 12) One does not have to accept this viewpoint.

Exercise 2. Study the usage of modal verbs followed, by per­fect and non-perfect infinitive.

1) Most primitive tools and devices must have been invented independently by different civilizations. 2) If there was some­one to put a question there must be somebody, sooner or later, to answer it. 3) There has to be a way out of any situation. 4) By that time the resources of the planet nay have been complete­ly exhausted. 5) A scientist may freely choose his line of rese­arch. 6) Everyone might be granted the right to be occasionally wrong. 7) They might have put the sample in freezer; it would be more effective. 8) At all the times there were ideas which should have been given more attention than they actually were. 9.) Good ideas should be written down before they are forgotten. 10) Not a single scientist shall work on the problems whose solution may be a threat to mankind. 11 ) They cannot have reached the sa­me level of development. 12) Nature would never be exhausted to challenge man with more riddles. 13) With our present-day tech­nology such phenomena could not have been observed in the labo­ratory; what was registered must, in fact, have been due to some malfunctioning of the recorder. 14) Intelligence of human qua­lity is not to be achieved overnight; there ought to pass plenty of time for anything comparable in complexity to human brain to evolve. 15) A true scientist will enjoy his work more than any­thing else and would often be prepared to sacrifice his weekends and vacation in order to proceed with his research.