1In 3- to 4-quart slow cooker, mix sweet potatoes, onion, carrots and lentils.
2In 8-inch skillet, heat oil over medium heat. Add curry powder, cumin, salt, pepper, gingerroot and garlic; cook 1 minute, stirring constantly. Stir in broth. Pour mixture into slow cooker; stir.
3Cover; cook on Low heat setting 5 to 6 hours.
4Increase heat setting to High. Stir in green beans. Cover; cook about 15 minutes longer or until green beans are crisp-tender. Serve topped with yogurt.