1. Gerunds
   1. after preposition
   2. after possessive adj or " 's"
   3. after the following words or expressions
      1. a. expressions
      2. b. verb
   4. "To" +gerunds
   5. the verbs of perception
2. Infinitives
   1. Infinitives(without "To)
      1. the following words or expressions are follow by bare infinitives
         1. a. (v)+ infinitives pattern
         2. b.(v)+object+infinitives pattern
   2. after adj
      1. a. used with adj of personal qualities, the preposition which follows is"of"
      2. b. used with adj of impersonal qualities the preposition which follows is"for"
   3. other infinitive patterns
      1. a1. Too+adj+to a2. It is+adj+to
      2. b. adj/ad.v+enough+infinitive
      3. c. not enough to=...to
      4. d. so+adj/adv+as+infinitive
      5. e. after only
   4. expressions are followed by"to"(infinitive)
      1. a. (v)+infinitive pattern
      2. b. (v)+object+infinitive pattern
3. the followed(v)are followed by either infinitive or gerund structure.