Sam, who is very good at math.
(example) Sam, who is very good at math, got an A on the test.
When the leaves turn orange.
(example) My favorite time of year is when the leaves turn orange.
Which is why she wants to visit Harry Potter Land.
(example) Maria loves Harry Potter, which is why she wants to visit Harry Potter Land.
The broken window
(example) The broken window was hard to clean up.
because they want to have fun
(example) They go to the skate park because they want to have fun.
Since Amy lives near me
(example) Since Amy lives near me, we ride the same bus.
Her mother went to the U of M so she wanted to go there too.
(needs comma) Her mother went to the U of M, so she wanted to go there too.
Jose walked to school most days today he took the bus.
(Options: . OR ; OR ,+FANBOYS) Jose walked to school most days, but today he took the bus.
Mohamed loved ice skating his sister did too.
(Options: . OR ; OR ,+FANBOYS) Mohamed loved ice skating. His sister did too.
He fell off his bike now he needs crutches.
(example) He feel off his bike; now he needs crutches.