Unmoulded time-words take -ed, but a few of them take -ed or -en; as,

Grave,graved,graved,
graven.

These following, as is shown by the Saxon, ought to take -ed rather than -en:—

Shape, shave, and swell were in Saxon moulded, and thence took -en.

There is a set of time-words which were weak, but are now endingless in their mark-word shape. They ended with a roof-penning -t or -d, and the roof-penning of the ending -ed ran at last into the roof-penning of the stems in the way shown on p. [22], and their mark-word shapes are the same as those for bygone time.

Shortened Shapes (p. [23]).