根据下面短文内容，在短文的空格处填上一个恰当的词，使短文完整、通顺。
Do you often like to use disposable (一次性的) chopsticks when    in restaurants? It’s time to drop this habit.
China produces 80 billion pairs of disposable chopsticks every year. “This is enough to cover Tian’anmen Square 363 times,” said Bai Guangxin, chairman of Jilin Forest Industry Group.
“The production of such chopsticks is a heavy burden (负担) on national forests,” Bai added. People need to cut      over 20 million 20-year-old trees to make way for this production.
Many people choose to use disposable chopsticks       they think that they are cleaner. However, many disposable chopsticks are not as       as people think. Some may even be toxic (有毒的), China Daily reported.
Several days ago, actor Huang Bo posted a message on his micro blog. He wrote that when he tried to wash the disposable chopsticks in a restaurant, he was      to find that the chopsticks turned the water yellow and gave off a bad smell.
Some scientists said the color and       of the chopsticks may show that they have something harmful such as sulphur (硫磺) and other chemicals (化学品). That’s bad        people’s health.
As Bai Guangxin suggested, it’s better that people carry their own chopsticks around. It doesn’t just help save the environment; it also     our own health.