2. e: gợi ý → He suggested going for a walk. >suggest + V-ing>
3. b: năn nỉ → She begged the robber not to hurt her. <beg sb to-V>
4. a: cảnh báo → She warned Ben not to go near the campfire because it was dangerous. <warn sb to-V>
5. d: hứa → His father promised to buy him a bicycle for his birthday. <promise to-V>