Infinitives dapat berfungsi sebagai noun, sebagai adverb, dan sebagai adjective.

A. Infinitives sebagai noun menjawab pertanyaan what

1. The two persons have agreed to meet again. The two persons have agreed not to meet again.
2. Do you prefer to study or do you prefer not to study?
3. We have decided to tell her the truth about what her boyfriend did last night. We have decided not to tell her the truth about what her boyfriend did last night.

B. Infinitives sebagai adverb menjawab pertanyaan why. Fungsi ini umumnya (if not all) akan menjadi lebih jelas kalau disisipi “in order” (atau so as, dan sejenisnya) sebelum infinitive bersangkutan.

1. I went to the shopping mall (in order) to buy something. I went to the shopping mall (in order) not to meet someone.
2. He entered your backyard (in order) to get his kite. He entered your backyard (in order) not to steal something.
3. My father usually puts on his sunglasses (in order) to protect his eyes from the sun ray. He puts on his sunglasses (in order) not to make himself look better.
4. We are quiet in order to let you rest. We are quiet in order not to disturb you.
5. He is always busy in order to get rid of his loneliness. He is always busy in order not to feel lonely.

C. Infinitives sebagai adjective menerangkan noun/pronoun, phrase or clause.

1. She wants to buy something to wear. (to wear menerangkan noun something). She wants to buy something to wear, not to collect. ((not) to collect menerangkan noun something).
2. He needs someone to talk. (to talk menerangkan noun someone). He needs someone to talk, not to love.
3. I am glad not to go to school today. ((not) to go (to school) menerangkan clause I am glad)
4. He’s sad not to be able to meet her tomorrow. ((not) to be (able to meet her tomorrow) menerangkan clause He’s sad).

Sekarang, kita kembali ke hal yang ditanyakan.

Kalau kita perhatikan Contoh B. 4 & 5, in order (atau as to) di kedua contoh kalimat ini adalah tidak optional agar kalimatnya makes sense (agar tidak sound akward).

So, penggunaan in order/so as yang disarankan oleh Learner’s Pocket sebenarnya khusus untuk kalimat yang menggikuti pola:

S + be + adjective + in order/so as + infinitive + …

walaupun kalimatnya bermakna positif sekali pun.

Sedangkan pada contoh B. 1-3 dimana penggunaan in order/as to-nya adalah optional, penggunaan not di depan infinitive tetap makes sense walaupun tanpa in order/as to.

Dan sekedar tambahan, jangan gunakan in order/as to pada infinitive yang berfungsi sebagai noun (poin A) dan sebagai adjective (poin C).

The two persons have agreed in order not to meet again. (INCORRECT)
Do you prefer in order not to study? (INCORRECT)
She wants to buy something to wear, in order not to collect. (INCORRECT)
I am glad in order not to go to school today. (INCORRECT)

for example:
we are quiet not to disturb you (INCORRECT)
we are quiet so as not to disturb you (CORRECT)

the correct one above is different pattern from the one you have namely on the negation section, you said just put NOT before infinitive.

please give me explanation…

Regards
Dhini

Pada umumnya, judul tidak merupakan sebuah kalimat. Judul bahkan bisa hanya terdiri dari sebuah kata, bukan?