As I understand for X不Y and X得Y forms, the full tone is optional and dependent on fluidity of speech. Can we allow tolerance for these, e.g. for 忍不住
Thanks for the report, it should definitely be ren3bu5zhu4 as the primary pronunciation for the simplified course, with ren3bu4zhu4 being accepted as a secondary one. The change will go out in the next update
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