叉车操作现场要有危险的地方要标上（），警告叉车操作人员不要接近。
参考答案：警告符号
The teaching building is _________ by many trees, some ______ over 30 metres.
A．surrounded, measuring
B．surrounded, measured
C．surrounding, measured
D．surrounded, measure
最能反映出长炒青老嫩程度的评比项目为（）
A.香气
B.叶底
C.滋味
D.外形
