Causative Form

Rule: Have + Object + Past Participle

This structure is used to describe when someone does something to you.

Examples:
Becky/ is testing/ eyes - Becky is having her eyes tested.
Ben/ has painted/ face - Ben has had is face painted.

You must pay attention to tense you are in, as this influences the tense of the sentence you're writing with the causative form.

Present Simple:  She cuts her hair  - She has her hair cut.
Pres. Cont.: She is cutting her hair - She is having her hair cut.
Past Simple: She cut her hair  - She had her hair cut.
Past Cont.: She was cutting her hair  - She was having her hair cut.
Future Simple: She will cut her hair  - She will have her hair cut.
Present Perfect: She has cut her hair - She has had her hair cut.
Pres. Perf. Cont.: She has been cutting her hair - She has been having her hair cut.
Infinitive: She must cut her hair - She must have her cut.

Exercise: http://www.englishexercises.org/makeagame/viewgame.asp?id=1759