"What Brown has done is to just cause an explosion of the black middle class."

She knew this was going to cause an explosion, and it did.

Two other factors may have come together to cause the explosion, the agency said today.

Officials said they did not know what had caused the explosion.

I don't see how they could have caused an explosion.

The government has said it is too early to say what caused the explosion.

"But the energy would not be enough to cause the explosion at an exact point in time."

Several hours later there still was no clear picture of what caused the explosion or anyone taking responsibility.

"They want to find out what caused the explosion," David said.

He may have caused the explosion with his new abilities.