_____ in thought completely, he didn’t even know what was going on.
Once harm is _______ to the eco-system, all species will ________, including man himself.
The stamp on the letter is an art, from _______ we can get a lot of cultural knowledge.
It is believed that a new kind of drug ______ by the scientists and they are hopeful that they will succeed in a few months.
Jenny nearly missed the flight ________ doing too much shopping.
If you receive a bunch of roses on Valentine’s Day, do you know what hidden meaning is _______ to it?