1. I can't think of (go) going to visit her in hospital without (buy)buying  some flowers.
=> Sau giới từ + Ving 
2. Don't hesitate (ask) to ask me if you have any questions.
=> Hesitate + to V: do dự trong việc gì
3. It was very kind of you (show) to show me the way to the post office.
=> It was + adj + of sb + to V 
4.  I am looking forward to (see) seeing him again.
=> Looking forward to + Ving: mong chờ việc gì 
5. I intend (study) to study  English to understand the cultures of foreign countries.
=> Intend + to V: có dự định