By the time
By the time the people who wanted ice cream arrived, Tom, John, and Lynn had picked up all the trash.
so that
The students went to the Square so that they could pick up trash.
in order to
The students went to the Square in order to clean up the trash.
Most of
Most of people in the Square were not students.
how long
How long were they at the Square?
It's not clear how long they were at the Square.
told
The professor told them that they should go to the Square.
The professor told them to go to the Square.
, which
Earth Day, which is a holiday to celebrate nature, was celebrated at the Square in Denton.
The students were excited about
The students were excited about celebrating Earth Day.
A number
A number of people came to eat ice cream.
because of
Because of Tom, John, and Lynn's hardwork, the Square was cleaned.
Because of their being sad, Tom, John, and Lynn stopped celebrating Earth Day.
The students couldn't understand why
The students couldn't understand why everyone left their trash on the ground.
, where
The Square, where the professor told them to go, is in Denton.
They should
They should have more trash cans on the Square.
therefore
Tom, John, and Lynn wanted to celebrate Earth Day; therefore, they went to the park to pick up trash.
Although
Although Tom, John, and Lynn picked up all the trash, people came and immediately trashed it.
Lynn wondered
Lynn wondered whether she should call some friends.
Lynn wondered whether to call some friends.
, most of whom
There were 15 people in the Square, most of whom were students.
should not have
The people should not have thrown their trash on the ground.
nevertheless
They picked up all the trash in the park. Nevertheless, people came and immediately trashed it.
such...that
The event at the Square was such a disappointment that they stopped celebrating Earth Day.
Dr. Smith was such an enthusiastic professor that he encouraged Tom, John, and Lynn to go to the Square to pick up trash.
What the students
What the students wanted to do was to celebrate Earth Day.
, whom
Dr. Smith, whom Tom, John, and Lynn have for biology, told them to go to the Square for Earth Day.
must be
Tom, Lynn, and John must be interested in science.
in fact
Not many people came to pick up the trash; in fact, only 18 people came.
That
That Tom, John, and Lynn care about the environment is clear.