Distinguishing Ш and Щ

Here are 6 pairs of word with ш and щ in different positions: - вешать (to hang) - вещать (to broadcast); - шалаш (a hut) - щадить (to have a merci); - уши (ears) - ущелье (canyon); - шум (noise) - щука (a pike); - шипеть (to hiss) - щипать (to pinch) - шелк (silk) - щелкать (to click).