根据句意、首字母或中文提示写出单词。 1. She is c_______. She feels certain of her own ability. 2. I can receive a c_______ if I pass the exams. 3. You must return your a_______ form by mail. 4. ORBIS is an _______ (国际) organization. 5. Friendship is the most _______ (有价值的) thing in the world.