Ex.1. Analyze these pairs of sentences and compare the predicates given there.

1. They are solving the equation at the moment. 2. He was dividing these numerals at 2 o’clock yesterday. 3. We have already reduced the fraction. 4. When I came back you had already replaced the terms in the equation. 5. They will have discussed the definition by 3 o’clock. The equation is being solved at the moment. These numerals were being divided at 2 o’clock yesterday. The fraction has already been reduced. When I came back the terms in the equation had already been replaced. The definition will have been discussed by 3 o’clock.
1. Are you changing the improper fraction to the whole number now? 2. Was she writing the decimal fractions at that moment? 3. Has he omitted the plus sign in this sentence? 4. Will you have translated the article by tomorrow? Is the improper fraction being changed to the whole number now? Were the decimal fractions being written at that moment? Has the plus sign been omitted in this sentence? Will the article have been translated by tomorrow?
1. The students are not multiplying these integers right now. 2. We were not subtracting the fractions when the teacher came in. 3. You have not divided the numerator yet. 4. The student had not proved the theorem by the end of the class yesterday. 5. They will not have checked the result of the calculation by 5 o’clock tomorrow. These integers are not being multiplied by the students right now. The fractions were not being subtracted when the teacher came in. The numerator has not been divided yet. The theorem had not been proved by the end of the class yesterday. The result of the calculation will not have been checked by 5 o’clock tomorrow.