What do you think?

• Do you think these discoveries were absolutely unexpected? Why?/Why not?

• Why are scientists often portrayed as mad or eccentric experimenters?

• Comment on the saying “The fortune likes those that are prepared”.

Focus on language

Read the sentences. What grammar tenses are used?

• We were tired because we had been experimenting all day long.

• After I had worked in the lab for a few weeks, I felt I knew the equipment

pretty well.

• They were making observations of the night sky for several years hoping to discover the planet they had calculated.

• First students had a short talk with a lab instructor about safety in the lab and then they were allowed to work with some chemicals.

• The lecture finished before we got there.

• The lecture had already finished before we got there.

Past Simple, Past Progressive, Past Perfect and Past Perfect Progressive We use … talk about an activity or situation that began and ended at a particular time in the past. We use … to say that something was going on around a particular time in the past or a longer background action or situation which was interrupted by a shorter action. We use … to speak about an action which happened before another past action. We use … to talk about an action or event continuing up to a specific time in the past. We put the emphasis on ‘how long’.

Practice

1. List time expressions under the correct tense heading. Some expressions can be used more than once.

for	before	by the time	first,
since	after	yesterday	until
when	while	as soon as	during
already	ago	at this time last year

Past Past Past Past

Simple Progressive Perfect Perfect Progressive

_______ ________ _______ ________

_______ ________ _______ ________

_______ ________ _______ ________

2. Complete the sentences with the correct Past tenses.

1. Class (begin, already) __________ by the time I (get) __________ there,

so I (take, quietly) __________ a seat in the back.

2. My group mate (discuss) ___________ something with professor when I (walk) __________ into the room.

3. It was midnight. I (study) ___________ for five straight hours. No wonder I

(get tired).

4. Millions of years ago, dinosaurs (roam) __________ the earth, but they

(become) __________ extinct by the time humankind first (appear) __________.

5. I (call) Kate at nine last night, but she (be, not) __________ at home. She (study) ____________ at the library.

6. Kevin suddenly realized that the teacher (ask) him a question. He couldn’t

answer because he (daydream) ____________ for the last ten minutes.

7. I (see, never) ___________ any of Picasso’s paintings before I (visit) ___________ the art museum.

8. The anthropologists (leave) ____________ the village when they (collect) ___________ enough data.

9. While Roger (write) ___________ an essay his roommate (clean) ___________ the room, so Roger (cannot) ___________ concentrate and (get) ____________ angry.

10. As I (pass) ____________ the hardest exam and (get) ___________ an excellent mark I (feel) ____________ a know-it-all.