Words are said to collocate when they are used regularly together in a language. Certain words must go together and if one is used and the other is omitted, the sentence becomes wrong.
The following are examples:
1. No sooner had- than(not when): No sooner had I opened the door than the thief fled.
2. Prefer-to(not than): She prefers Engineering to Biochemistry
3. Hardly had-when(not than): Hardly had the journey started when the car engine developed a fault.
To be continued
