You have seen that five of these twenty words have <rr> because of simple addition and five of them have <rr> because of twinning. Find these ten in the list above and cross them off.
2. When the prefixes ad-, com-, and in- are added to stems that start with an <r>, they assimilate to _______, _______, and ______.
3. Ten of the twenty words above with [r] spelled <rr> start with an assimilated form of ad-, com-, or in-. Find them, write them in the left column below, and analyze them to show the assimilation that leads to the <rr>:
Analysis: Prefix + Stem
in+ r + rigation
4. The following words each contain two prefixes and a stem. See if you can analyze them to show where the <rr> comes from: