VOA慢速英语:宇航员将首次在太空烤饼干

dough – n. a mixture of flour, water, and other ingredients that is baked to make bread, cookies, etc.

heating element – n. the part of an electric heating appliance in which the electrical energy is transformed into heat

salad – n. a mixture of raw green vegetables (such as different types of lettuce) usually combined with other raw vegetables

silicone – n. a chemical compound that does not let water or heat pass through and that is used to make rubber and grease and in plastic surgery