 Complete the following phrase:  Two weeks after the war began for Britain, HMS Courageous was on an anti-submarine patrol with only a small screening force. It was sunk by U-29. HMS Ark Royal might well have been sunk the same week by U-39 if the U-boats torpedoes had not been defective. Thereafter, such carriers were regarded by the Admiralty as too vulnerable to be used for anti-submarine patrols. Eight months later, HMS Glorious was evacuating aircraft during the 