YB65型条盒包装机出现胶水缸锁不紧的原因是条盒胶水缸不到位、胶水缸锁紧手（）柄和胶水缸位置检测器失效。
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I saw Jack yesterday. He told me that he would stay here _____ the end of this year.
A．at
B．by
C．for
D．till
补气生血法
