She won't have any troubles learning to ride a horse - you can see she's a natural. She won't have any troubles (learning) to ride a horse - you can see she's a natural. She won't have troubles (studying) this and that book at the same time. She loves talking to people while (eating). I wouldn't believe she would know everything in this book without(learning). Do the words learning and eating and learning and studying are nouns or verbs in these sentences?