I wish that, as in Would that I could stop working and go hiking with you. For a synonym, see if only.
That vs. WhichTo understand when to use that vs. which, it’s important to keep in mind the difference between and restrictive and nonrestrictive clauses. In formal American English, that is used in restrictive clauses, and which in used in nonrestrictive clauses. A restrictive clause contains information that limits the meaning of the thing being talked about. For example, in the sentence “Any book that you like must …
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.