but和so可以一起用吗

　　The show was well performed, but so safe and predictable.

　　演出不错，只是太四平八稳，缺少新意。

　　But so had those who were high in status ．

　　但那些地位高的人也是。

　　He was a fine young man, but then so had his father been

　　他年轻有为，不过他父亲也曾经是。

　　This disorder is easily diagnosed but not so easily treated.

　　这种疾病容易诊断，但却不容易治疗。

　　He paused enough to consider the options but never so long as to losethe initiative.

　　他停顿了一会儿权衡自己有哪些选项，但并没有久到丧失主动权。