I can talk about behaviour (Teenage behaviour)

Question 1

messy

Answer 1

dirty or untidy

mess n. SB can make a mess. : STH can be in a mess.

Question 2

to pull your weight

Answer 2

to work as hard as everyone else in a job or activity

SYN. TO DO YOUR FAIR SHARE.

Question 3

go on and on( about something, at somebody)

Answer 3

to keep talking (about sth or to sb) in a boring way.

Question 4

nag

Answer 4

keep complaining about sb’s behaviour.

Question 5

unappealing

Answer 5

not pleasant or attractive. OPP appealing.

Question 6

life-threatening

Answer 6

likely to cause death( heere it is being usedhumorously).

Question 7

lay down rules

Answer 7

say officially what the rules are.

Question 8

set an (or a good/bad) example

Answer 8

behave in a way that others may copy.

Question 9

give in (to sb/sth)

Answer 9

to agree to do something that you don't want to do 
SYN capitulate (to sb/sth).

Question 10

fuss

Answer 10

if you make a fuss about sth, you become angry and complain about sth which probably isn’t important. KICK UP A FUSS

Question 11

kick up a fuss/row/stink

Answer 11

to show great anger about something, especially when this does not seem necessary.