Definition: In this task, you need to write a topic word from the given fact. The topic word must have at least one word overlap with the given fact. The topic word often involves adding a new word from a related concept. In your topic word, use at least one word from the given fact. Topic words with two or more words work best.

Positive Example 1 -
Input: Fact: pesticides cause pollution.
Output: pollution harms.

Positive Example 2 -
Input: Fact: pesticides cause pollution.
Output: modern farming pesticide.

Negative Example 1 -
Input: Fact: pesticides cause pollution.
Output: computer harms.

Negative Example 2 -
Input: Fact: pesticides cause pollution.
Output: toopaste helps.

Now complete the following example -
Input: Fact: the gravitational pull of the Moon on Earth 's oceans causes the tides.
Output: 


Output:
earth ocean.
earth world.
gravitational pull.
ocean pacific.
ocean tides.
oceans pacific.
tide current.
tides are caused.
tides cause damage to shores.
tides cause.
tides gravity.
tides make waves.
tides ocean water.
tides water.
tides wave.