add faq

README.md

@@ -121,6 +121,14 @@ const instance = import.sync(x);
 
 ## FAQ
 
+### Is Import Sync a module loading phase?
+
+No, unlike `defer` and `source`, `import.sync` is not a phase, it is a new meta property like `import.meta`.
+
+No syntax is supported for `import sync mod from 'mod'`.
+
+To guarantee that a graph is sync upfront, instead see see the [Module Sync Assert](https://github.com/tc39/proposal-module-sync-assert) proposal, which may provide an import attribute or otherwise.
+
 _Post an [issue](https://github.com/guybedford/proposal-import-sync/issues)._
 
 [Defer Import Eval]: https://github.com/tc39/proposal-defer-import-eval