Present Indicative.—a. The primary personal endings are added to the stem with the strong form in the singular and the weak form in the dual and plural.
b. In the 2 sing. τίθης, ἵ_ης, ἵστης, δείκνυ_ς, etc., ς has been added to the stem. This ς is obscure in origin, but cannot be derived from -σι. τιθει-ς is rare.
c. 3 sing. τίθησι, ἵστησι, etc., with -σι for -τι ( cross463 c).
d. 3 plur. τιθέα_σι, ἱστᾶσι, etc., from τιθέ-αντι, ἱστά-αντι ( cross463 d).
e. For the retention of ς in τίθε-σαι, etc., see cross465 a, b, and N. 2.
f. δίδομαι in the middle present and imperfect is used only in composition, as ἀποδίδομαι. But the simple form occurs in the passive.
Herbert Weir Smyth [n.d.], A Greek Grammar for Colleges; Machine readable text [info] [word count] [Smyth].