1. Johnís living here for the past five years.
Correction: John's been living here for the past five years.
The present perfect continuous takes the form HAS + BEEN + VERB-ing; e.g., John has been living here for the past five years.
John's living here is a gerundival phrase, a noun, which makes example 1. ungrammatical because it lacks a verb; Cf. John's living here for the past five years is driving me crazy.
2. I wrote ten letters so far this evening.
Correction: I have written ten letters so far this evening.Explanation
The adverbial phrase so far means from then up until now, a meaning which is compatible with the present perfect; e.g., So far, that is, up until now, I have written 10 letters.
3. Look! That girl fell down.
Correction: Look! That girl has fallen down.Explanation
The present perfect tells us that the event happened recently, between now and some unknown time in the past. Use the present perfect to place focus on an event, not when the event happened; Cf. Look! Just now that girl fell down.
4. Weíve heard from Peter two weeks ago.
Correction: We heard from Peter two weeks ago.Explanation
The present perfect is not compatible with time adverbials expressing definite time; e.g., two weeks ago; Cf. We've heard from Peter before.
5. Heís been smoking 10 cigarettes today.
Correction: He has smoked 10 cigarettes today.Explanation
The present perfect continuous expresses an event as ongoing. Example 5. above means the man has been smoking the same 10 cigarettes all day. That's odd, wouldn't you say?
What the writer wants to say is that the man has smoked 10 cigarettes so far today. Notice
the PP compatible time adverbial 'so far'.
6. Iíve painted the house. I expect Iíll finish it on Sunday.
Correction: I've been painting the house. I expect I'll finish it on Sunday.7. What happened? Iíve been cutting myself.
The house is still in the process of being painted. The event is ongoing, so use the present perfect continuous. You could use the simple continuous; e.g., I'm painting the house, but this exercise is about using the present perfect.
Correction: Iíve cut myself.
The present perfect continuous expresses an event as ongoing from some unknown or unstated time in the past up until now, the present. Example 7. means the person is still in the process of cutting himself/herself.