皮皮学，免费搜题
登录
搜题
【单选题】
Air pollution,together with littering,______ many problems in our large industrial cities today.A.
cause
B.
caused
C.
causes
D.
causing
拍照语音搜题，微信中搜索"皮皮学"使用
参考答案：
参考解析：
知识点：
皮皮学刷刷变学霸
举一反三
【简答题】scale(s)______
【简答题】S1:What is the range scale of the echo sounder?S2:Echo sounder is at 10 meters range scale.Q:What are they talking about?A. The radar system of the ship. B. The communication system onboard. C. The ec...