Complex sentence: Under Michael Ignatieff, Regan served as Liberal Critic for Natural Resources, and later, Public Works and Government Services and also as the Liberal Natural Resources Critic under leader Justin Trudeau and the Vice-Chair of the Standing Committee on Natural Resources.
Split into simpler sentences: Under Michael Ignatieff, Regan served as Liberal Critic for Natural Resources, and later, Public Works and Government Services. He is currently acting as the Liberal Natural Resources spokesperson under leader Justin Trudeau and serves as Vice-Chair of the Standing Committee on Natural Resources.