---Does your brother always work so hard?---Yes. he catches a cold or has a fever sometime

问题补充：

---Does your brother always work so hard?

---Yes. he catches a cold or has a fever sometimes

A. whenever

B. no matter how

C. even though

D. although

答案：

A. whenever

B. no matter how

(答案→)C. even though

D. although

解析：此处为一省略句，even though表示“即使”。