✔ 最佳答案
Please feel free to contact (for example) Tom by 9276124 or via email :
[email protected].
Feel(v) free(adv) to(prop.) contact(v)
If no 'to' is added to the above sentence, two verbs would appear in the same sentence which is inappropriate.
A grammatical error is there avoided by inserting the 'to' in between~~~