1. We (were translating) the arlicle during the whole lesson yesterday
2. We usually (translate) texts using special dictionaries.
3. The students usually (write) their fmal tests at the end of each term.
4. The students (are writing) their final test. Keep silence.
5. When you (to come) in an hour we (shall discuss) the results of the test.
6. I (looked) up the words in the dictionary while he (was reading) the text.
7. The teacher ( explained) this grammar rule at the last lesson.
8. The teacher (was explaining) the new grammar rule when I ( came) in.
9. During some decades of the last cermry scientists (were trying) to explain this unusual phenomenon.
10. A true scientist always ( tries) to explain unusual phenomena.
11 This plant (produces) various kinds of instruments.