1 . We need free ourselves from _________ (消极的) attitude. (根据汉语提示单词拼写)

2 . Going from junior high school to senior high school is really __________(challenge). (所给词的适当形式填空)

3 . In order to make further progress in the field of science, we should be c__________ about everything around. (根据首字母单词拼写)

4 . Hearing a child stolen, many ________(焦虑的) parents dare not ask their kids to go out. （根据汉语提示单词拼写）