- For centuries the British regarded their navy as their principal bulwark against invasion.
- The fortified city of Singapore was once considered unconquerable. In 1942, however, this citadel fell to the Japanese.
- I am better than Jack in English but not in math;that is his forte.
- The robust young pitcher performed with his usual vigor for seven innings, but he weakened in the eighth and was removed from the game.
- If you feel enervated by the heat, try a swim in the cool ocean. It will invigorate you.
- Excuses for not handing work in on time vary. Some are flimsy, as, for example, "I left it at home. " Others are more cogent, such as a physician's note.
dynamic 精力充沛的；有力的 （反义词：undynamic）
- If you elect Jessica, you may be sure she will present our views forcefully and energetically. She is a very dynamic speaker.
- Our hopes for an easy victory sank when our opponents took the field. They were much taller and huskier, and they looked formidable.
- Before World War II, the French regarded their Maginot Line as an impregnable bulwark against a German invasion.
robust 强壮的 （反义词：frail， feeble）
- The lifeguard was in excellent physical condition. I had never seen anyone more robust.
- After the dog got the ball, I tried to dislodge it from her tenacious jaws, but I couldn't.
- Your protest was too mild. If it had been more vehement, the dealer might have paid attention to it.