JT connects certain conjunctions to time-expressions that are not
well-formed noun phrases, like "last week". and "this week".

          +-----CO-------+
          +----JT----+   |
          |    +--DT-+   |
          |    |     |   |
	Until last week, I thought she liked me

With time expressions that are well-formed noun phrases like
"this week", no JT is necessary; the phrase can serve as a
prepositional object using its ordinary J- connector.  See
"DT" for more discussion of time expressions.