在低气温下进行高处作业时间不宜超过()h。 ["0.5","1","1.5","2"]
1. import java.util.*; 2. public class Example { 3. public static void main(String[] args) { 4. // insert code here 5. set.add(new integer(2)); 6. set.add(new integer(l)); 7. System.out.println(set); 8. } 9. } Which code, inserted at line 4, guarantees that this program will output [1,2]? () [" Set set = new TreeSet();"," Set set = new HashSet();"," Set set = new SortedSet();"," List set = new SortedList();"," Set set = new LinkedHashSet();"]
环境污染源主要有哪些?
一种学习对另一种学习的影响称为学习的() ["强化","迁移","反馈","联结"]
重质燃料油对水分有何要求?
简述英国学前教育课程概况