In positieve zinnen?
+ am/are/is + ww + ing = I/we/you/he/she/it + am/are/is + working.
In negatieve zinnen?
- = am/are/is + not + ww + ing = I/we/you/he/she/it + am/are/is + working
In vragen?
? = am/are/is + I/we/you/he/she/it + ww + ing = Am/Are/Is + I/we/you/he/she/it + working.