In this section, you will hear several passages. Listen to the passages carefully and then answer the questions that follow.

What is the purpose of this talk

A. To encourage people to participate in a club activity.
B. To introduce a new kind of bicycle.
C. To inform beginning cyclists about New Jersey’s traffic laws.
D. To warn tourists about bicycling on the roadways.

焊接铬镍奥氏体不锈钢时，为提高耐腐蚀性，焊前应进行预热。( )