some(-)time
说“若干时间”该用some time。例如：He went some time ago. 和She stayed here for some time. 说“在某一时刻地”或“若干时间地”也该用some time。例如：He went some time last week. 和She stayed here some time. 但也可以用sometime或some-time。
在He was sometime professor of physics at the university和Dr Spencer, (the) sometime professor of physics at the university, will publish a new work before long等句子里的sometime作“从前地（的）”解，不可改作some-time或some time。说“有时地”该用sometimes。例如：He sometimes writes to me in French.
