My attempt:
Quote:
1. He laughed and raised his hands as a sign of giving in
2. It is necessary that you take part in discussing this question
3. There are many advantages and disadvantages of having a car
4. The disadvantage of his when driving a car was that he doesn't/does not have a driving licence
5. The children were running about at the bank of the river
6. Do you know who I run(ran?) into at the library?
7. He ran into debt because he had bought a house.
I'm not sure about number 4 though. It could be changed around more to something like:
'
When driving a car, the disadvantage of his was that he doesn't/does not have a driving licence'.
If there is only 1 disadvantage then the above is fine but if there are many:
'
When driving a car, a disadvantage of his was that he doesn't/does not have a driving licence'.
For number 6, you say: '
do you know who I run into at the library?' when you run into them regularly.
Maybe it's better to say: '
do you know who I usually run into at the library?'.
And you say: '
do you know who I ran into at the library?' if it only happened once at a previous time.