碗扣式钢管脚手架在拆除前，现场的专职安全员应对操作人员进行有针对性的安全技术交底。
参考答案：错
A strange sound ______ yesterday evening. [ ]
A. was heard
B. hears
C. heard
D. is heard
下列果树，适合在暖温带栽种的有[ ]
A．柑橘
B．苹果
C．梨
D．芒果
