The existence of a developmental sequence for the acquisition of specific complex syntactic structures in English was investigated through an analysis of eight studies of Danish subjects. The studies involved Danish speaking subjects acquiring English as a second language at ages 7-10, 13, and 18. The evidence from these studies demonstrate a developmental sequence of linguistic stages with each of the structures acquired in sequential order. General syntactic principles are at work despite the different learning situations and learner skills. Gradual development, degrees of understanding, and the importance of contextual and interpersonal cues must be considered when evaluating variations in comprehension. The distinction between conceptual development and the mastery of the syntactic rules studied is discussed. Performance strategies relying on syntactic/semantic cues varying according to experimental setup and developmental stage are noted. (RW)