Which of the following is difficult for robots to do at present

单项选择题In a true sense, plateways are the earliest and most primitive railways invented by ______.

单项选择题At first, locomotives could not popularize themselves because they ______.

单项选择题The best way to save ozone is ______.

单项选择题Why should governments ensure the careful handling and recycling of the CFCs now in use

单项选择题Apart from the majority of countries, the U. K. has ______ to form the whole part of its constitution.