The question of what kind of practice can help learn a foreign language (L2) has been the object of much research in the field of second language acquisition. Although targeted practice cannot suffice to attain proficiency in L2 because meaningful interactions are required, it has nevertheless proved to be beneficial (Nakata & Suzuki, 2019). One such technique of targeted practice has been the object of recent research and shows promising results: interleaved (vs. blocked) practice. Interleaved practice consists in mixing different categories of items to be learned, or different types of exercises, instead of blocking them together. This type of practice is particularly beneficial for learning to distinguish different categories that seem similar, e.g., painting styles (Kang & Pashler, 2012), bird species (Birnbaum et al., 2013), mathematical functions (e.g., Rohrer & Taylor, 2007), or conjugated verb forms in a foreign language (Pan et al., 2019). It therefore has potential to help learners acquire syntactic structures that are difficult to master because they look similar but obey different rules, in particular the use of inversion in English in main vs. embedded WH- questions or the difference between DO-support constructions and the perfect aspect using auxiliary HAVE. In this talk, I will review recent conflicting evidence for the effectiveness of interleaved practice and present preliminary results of a study conducted with 48 intermediate French learners of English studying inversion and DO vs HAVE auxiliary constructions in an interleaved vs. blocked manner.