Select the main idea of the paragraph.

Cannons nearly always betray an old wreck at the bottom of the ocean. After a few years, when the hull decays and collapses, the cannons remain intact. Their straight lines are an immediate giveaway, even when they have become completely covered with coral, for nothing natural in the sea is perfectly straight.

Their straight lines are an immediate giveaway.
Cannons nearly always betray an old wreck at the bottom of the ocean.
After a few years, when the hull decays and collapses, the cannons remain intact.

Choose the sentence that does not fit.

Watching a bird build its nest is interesting. First, it chooses a safe, secure spot, out of the reach of curious humans. Then it starts to work, carrying bits of string, small twigs, and other things it needs. There are many kinds of birds.

There are many kinds of birds.
Watching a bird build its nest is interesting.
Then it starts to work.

Choose the sentence that does not fit.

I thought the time would never arrive. I kept watching the second hand, holding my breath and waiting for it to reach twelve. Craig nudged me. After what seemed like hours, the bell finally rang.

I thought the time would never arrive.
After what seemed like hours, the bell finally rang.
Craig nudged me.