5. INCORRECT -- I can't get across him/get through to him.Doesn't he understand that his future depends on the exam? (make smn understand smth). **** So there are two patterns usually for indirect objects used with verbs. For instance, "I gave him the book." or "I gave the book to him." However, some verbs cannot take the first pattern. This is one of those verbs. So you have to say one of these:
a. I can't get through to him.
b. I can't get it through to him. (if there is a direct object)
c. I can't get my idea through to him.
d. I can't get it across to him. (with the pronoun "it")
e. I can't get this simple plan to save money across to him. (with a direct object)
f. I'm not good at getting my ideas across.
g. My plan didn't really get across.
6. CORRECT -- Get out of the car, quickly! (leave a car).
7. INCORRECT -- Have you heard about Ann? She managed to get into doctor last month (start a career/profession). *** As Jessica said, in this particular example, you would have to use "managed to become a doctor." If you want to use "to manage to get into something", then you need to use the field name, not the profession name. For instance, "She managed to get into NURSING.", not "She managed to get into NURSE." The same holds with doctors. So "She managed to get into the medical field.", etc.