CREATE TABLE table_28079 ("Series #" FLOAT, "Title" TEXT, "Directed by" TEXT, "Written by" TEXT, "Original air date" TEXT, "Production code" TEXT, "U.S. viewers  ( million ) " TEXT)

Who was the director for episodes that were written be Matthew Lau?
SELECT "Directed by" FROM table_28079 WHERE "Written by" = 'Matthew Lau'
SELECT "Directed by" FROM "table_28079" WHERE "Written by" = 'Matthew Lau'