1. At the news that his favourite star took drugs, he was too _______（吃惊的） to speak.
2. The air in the balloon _______（膨胀） when heated.
3. Switch off the _______（电） before you attempt any repair.
4. The government has an interest in importing scientific _______（设备）.
5. The house Osama bin Laden once lived in looked _______（普通的）.
