根据句意和汉语注释，写出单词的正确形式。
I wonder how many ______ ORBIS doctors perform during their visit to a poor country. (手术)
Come and join our summer English camp! It’s an _______ chance for you to improve your spoken English. (极好的)
In our _______class, the students had to practise on each other.（急救的）
I have forgotten those ________names, but I will always remember their faces. (绅士)