机动链锯不得使用（）发动机用机油和（）水冷发动机的机油。
参考答案：四冲程；二冲程
Carter's team found the tomb of King Tutankhamun was the most important tomb _____ had ever been found.[ ]
A. what
B. that
C. where
D. which
动车组缓冲装置的主要种类有哪些？
