DEFECTIVE STRONG VERBS.

247. There are several verbs which are lacking in one or more
principal parts. They are as follows:--

PRESENT. PAST. | PRESENT. PAST.
|
may might | [ought] ought
can could | shall should
[must] must | will would

248. May is used as either indicative or subjunctive, as it has two
meanings. It is indicative when it expresses _permission_, or, as it
sometimes does, _ability_, like the word _can_: it is subjunctive when
it expresses doubt as to the reality of an action, or when it
expresses wish, purpose, etc.

[Sidenote: _Indicative Use: Permission. Ability._]

If I _may_ lightly employ the Miltonic figure, "far off his
coming shines."--WINIER.

A stripling arm _might_ sway
A mass no host could raise.--SCOTT.

His superiority none _might_ question.--CHANNING.

[Sidenote: _Subjunctive use._]

In whatever manner the separate parts of a constitution _may_ be
arranged, there is one general principle, etc.--PAINE.

[Sidenote: (_See also Sec. 223._)]

And from her fair and unpolluted flesh
_May_ violets spring!
--SHAKESPEARE.

249. Can is used in the indicative only. The _l_ in _could_ did
not belong there originally, but came through analogy with _should_
and _would_. _Could_ may be subjunctive, as in Sec. 220.

250. Must is historically a past-tense form, from the obsolete
verb _motan_, which survives in the sentence, "So _mote_ it be."
_Must_ is present or past tense, according to the infinitive used.

All _must concede_ to him a sublime power of action.--CHANNING

This, of course, _must have been_ an ocular
deception.--HAWTHORNE.

251. The same remarks apply to ought, which is historically the
past tense of the verb _owe_. Like _must_, it is used only in the
indicative mood; as,

The just imputations on our own faith _ought_ first _to be
removed_.... Have we valuable territories and important
posts...which _ought_ long since _to have been surrendered_?--A.
HAMILTON.

It will be noticed that all the other defective verbs take the pure
infinitive without _to_, while _ought_ always has _to_.

Shall and Will.

252. The principal trouble in the use of _shall_ and _will_ is the
disposition, especially in the United States, to use _will_ and
_would_, to the neglec