ASKING NECESSITY AND OBLIGATION

Here are some examples of phrases and sentences that can be used to express or express obligation and the Necessary .

A. Obligation

1 . using adjectives : Obligatory , Compulsory , Needless , Unnecessary

Example Sentence :

• It is obligatory for the people to Participate in education .
• Entering elementary school is compulsory in Indonesia .
• That's a needless thing to speak with him .
• It's unnecessary to sit under the tree for hours .
• Etc. .

2 . Use nouns : Obligation , Compulsion , a Need , Necessity

Example Sentence :

• There is a legal obligation to enter the army .
• It's compulsion to obey your parents .
• It's a need for everybody to eat nutritious food .
• Is it a necessity for man and woman to sit apart ?

3 . Use Verbs : Oblige

Example Sentence :

• My father obliged me to study every night .

4 . Use Capital Auxiliaries : Must , Have to , ought to , Should

Example Sentence :

• You must obey your parents .
• Every Muslim must pray five times a day .
• I have to go now .
• You ought to repair my watch .
• Those shoes should be repaired .
• I ought to wake up early
• Etc. .

NOTE :
The word "must " have a very strong sense of ( strong ) . The use of the word " must" is more Likely to have meaning on a must already be an obligation to do .

B. Necessary

Example Sentence :

• I think it's not your necessity to follow the party .
• To sleep at noon is being my necessity .

source: http://bahasainggrisonlines.blogspot.com/2013/06/contoh-kalimat-expressing-obligation-and-necessary.html