乙二膝四乙酸二钠简称（），是四元酸，在溶液中存在（）种型体。
参考答案：EDTA；七
The little boy often _________ glasses, and he likes to go for a walk _______ his dog. [ ]
A. puts on; with
B. wears; with
C. puts on; has
D. wears; has
（）应为其领土内的港口设施和进入其港口前的船舶或在其港口内的船舶规定保安等级并确保向它们提供保安等级方面的信息。
A.缔约国政府
B.指定当局
C.主管机关
