问题
选择题
Scientific experiments __________ by students without the teachers’ instructions can be dangerous.
A．carry out
B．carrying out
C．carried out
D．carrying
答案
答案：C
考查非谓语动词experiments与carry out为动宾关系要用过去分词作定语。句意：学生没有老师指导做科学实验有可能有危险。