Step 1 Revision
1 Ask the Ss What were you doing when I came into the classroom?
Get different answers. Then practise short form replies： Were you talking? Was he/she reading a book? etc.
2 Revise while： ask What were you doing while you were waiting for me? Help the Ss to use while + Past Continuous Tense.
3 Revise the difference between when + Simple Past Tense and while + Past Continuous Tense.
Draw a diagram on the Bb to show the difference：
when + Past Simple Tense：
Step 2 Practice
SB page 20， Part 1. Ask the Ss two questions as an example， then let them ask and answer in pairs.
SB page 20， Part 2. Again， do one as an example. (You may wish to draw a diagram on the Bb to show its meaning.) Then get the Ss to make up their own examples.
Step 3 Practice
Wb Lesson 20， Ex. 1. Go through the questions; ask one or two Ss as an example. Then the Ss carry out the task in groups. When they have finished， ask some Ss to report their answers to the class.
Step 4 Stress
Wb Lesson 20， Ex. 2. Speech Cassette Lesson 20. Play the tape for the Ss to listen and repeat. Focus on any problems. Make sure the Ss all stress the first syllable. Note that in the first group， there are two syllables. But in the second group， there are three. If time allows， show Ss flashcards with the words written on them. Get the Ss to read the words. Pay attention to the stress.
Step 5 Checkpoint 5
Go through Checkpoint 5. Discuss any problems that arise. Practise the useful expressions， making sure the Ss understand their meaning and usage.
Step 6 Test
Draw these time lines on the Bb：
got up cleaning having
his room lunch
left shopping came
doing her having
watching teaching Polly
TV to talk
Give these questions orally. Tell the Ss to answer them in full sentences：
1 What was Kate doing when Jim got up?
2 What was Jim doing while Kate was watching TV?
3 What was Kate doing when Jim came home?
Ask the Ss to write three more sentences about the time lines.
Step 7 Workbook
Wb Ex. 3. Ss work in pairs. Check the answers with the whole class. The answers are：
standing， happening， accident， hurt， travelling， while， corner， badly， sorry， dangerous， careful.
Finish off the Workbook exercises.
Revise the language items in this unit.
The student on duty may prepare questions using the Past Continuous Tense for the next lesson.