— Look, it ________ again. — Yeah. This is the third snow we ________ this spring. A.will snow; are havingB.has snowed; had had C.is snowing; have hadD.snows; have had

步骤 1：分析句子时态
第一句 "Look, it ________ again." 表示当前正在进行的动作，因此应使用现在进行时，即 "is snowing"。
步骤 2：分析第二句时态
第二句 "This is the third snow we ________ this spring." 表示从过去到现在已经发生的动作，因此应使用现在完成时，即 "have had"。
步骤 3：选择正确答案
根据以上分析，正确答案应为 "is snowing; have had"，即选项 C。