AmexRuislip
Retired Spy 🕵️♂️
Maybe you did better than you think.
Question 2 is wrong.
I threw the ball further than John.
The rain caused further flooding in the region.
My house is further from the station.
All of the above are correct. In British English, further and farther can both be used in relation to distance.
Question 4 is also wrong.
The quiz that tested grammar knowledge was very difficult.
The quiz which tested grammar knowledge was very difficult.
The quiz, which was very difficult, tested grammar knowledge.
All of these are correct. Which or that can be used to refer to things in a defining relative clause (like the first two sentences). Which can be used in a non-defining clause.