1. You … be very attentive and careful if you carry out this experiment.
a) should; b) can; c) may; d) had to.
2. The electron spectrometer used for the research … to be of a new type.
a) must; b) is; c) are; d) may.
3. Theoretically any element … be able to force any element below it in the series.
a) can; b) might; c) should; d) is; e) may.
4. Liquid air … be evaporated.
a) may; b) must; c) can.
5. A substance … be crystalline and show no external regularity.
a) had to; b) may; c) should.
6. No animal … live without oxygen.
a) can; b) may; c) should; d) had to.
7. You … remember the properties of matter.
a) may; b) must; c) have to.

deniza0906    1   28.03.2020 16:13    1