whose paper is this?It ——be kangkang‘s ,he alwals forgets to

must
must be 一定是
因为后面有always总是
结合语境便可得出

must

must
根据后文的“he always forgets to write name”可以知道选must，表示肯定推测

may吧我觉得，它又没说一定是，应该是可能是吧。。

是must。因为maybe是副词，副词是用来修饰动词的，而maybe前面是it，it不是动词，所以用must。而且句子后面提到“he alwals forgets to write name”，既然你确定他经常忘写名字，那肯定就是用must，用maybe就很别扭。