Ex.1. read the sentences. find the predicate (2) and define the form of the verb ( 1. after that group the chemical elements. 2. mark the time of the reactions in your laboratory-book. 3. after that radio this important information to the centre. 4. a lot of powerful elevator pumps deliver oil from the tankers to the oil tanks. 5. first mark and then number all the flasks containing acids. 6. after that oil the machine. 7. the device pumps the oil from the well. 8. in this place the buses round the corner. 9. there are four flasks on the desk, containing some mixtures. add some water to the mixtures. the mixtures are dissolving. after that filter the solutions. 10. there are clocks that mark the time with an accuracy of one second per 300 years.
2. mark - the imperative mood,
3. radio - the imperative mood,
4. deliver - the Present ind.,
5. mark, number - the imperative mood,
6. oil - the imperative mood,
7. pumps - the pres.Ind.,
8. round - the Pres.Ind..,
9. there are, add - the imperative mood, are dissolving - the Pres.Cont., filter - the imperative mood,
10. there are, mark - the Pres.Ind.