直接安装在可燃材料表面的灯具，应采用标有（）标志的灯具。
A.
B.
C.
D.
参考答案：B
Which of the following statements regarding primary and secondary markets is FALSE()
A. Secondary market transactions occur between two investors and do not involve the firm that originally issued the security.
B. New issues of government securities can be sold on the primary market.
C. Prevailing market prices are determined by primary market transactions and are used in pricing new issues.
