EAP 140 AM - WANG, Lingshan - Week 2 1/4

We named the words such as can, may, should,must, and shall modal verbs.  We also consider ought to is a modal verb.  When we want to show certainty, necessity, and possibility, we can use use modal verbs with base form verb. 

e.g
1) People can easily find the problem when they watching this film.
2) I must finish my homework before my parents come back.
3) We should protect environment instead of damage to the environment.

If you want to use a verb in the passive voice, you need to use a form of be with the past participle.  

e.g
1）This book was written by my friend Lisa.
      This sentence use simple past tense.
2）This building will be built in next year.
      This sentence use simple future tense.
3）This song is being played all the night.
      This sentence use present progressive tense.