Complex sentence: He enjoys working with Harriet and they are able to make progress until Harriet learns that her new boyfriend, British special forces captain Robert Meyers (Tom Mison), is missing in action.
Split into simpler sentences: He enjoys working with Harriet and they are able to make progress. Their enthusiasm is interrupted, however, when Harriet learns that her new boyfriend, British special forces captain Robert Meyers (Tom Mison), is missing in action.