be able"). The silent l in the spelling of could results from analogy with would and should. Similarly, may and might are from Old English mæg and meahte, respectively present and preterite forms of magan ("may, to be able"); shall and should are from sceal and sceolde, respectively present and preterite forms of sculan ("to owe, be obliged"); and will and would are from wille and wolde, respectively present and preterite forms of willan ("to wish, want"). The aforementioned Old English verbs cunnan, magan, sculan, and willan followed the preterite-present paradigm (or, in the case of willan, a similar but irregular paradigm), which explains the absence of the ending -s in the third person on the present forms can, may, shall, and will. (The original Old English forms given above were first and third person singular forms; their descendant forms became generalized to all persons and numbers.) The verb must comes from Old English moste, part of the verb motan ("to be able to, be obliged to"). This was another preterite-present verb, of which moste was in fact the preterite (the present form mot gave rise to mote, which was used as a modal verb in Early Modern English; but must has now lost its past connotations and has replaced mote). Similarly, ought was originally a past form—it derives from ahte, preterite of agan ("to own"), another Old English preterite-present verb, whose present tense form ah has also given the modern (regular) verb owe (and ought was formerly used as a past tense of owe). The verb dare also originates from a preterite-present verb, durran ("to dare"), specifically its present tense dear(r), although in its non-modal uses in Modern English it is conjugated regularly. However, need comes from the regular Old English verb neodian (meaning "to be necessary")—the alternative third person form need (in place of needs), which has become the norm in modal uses, became common in the 16th century. Syntax A modal verb serves as an auxiliary to another verb, which appears in the infinitive form (the bare infinitive, or the to-infinitive in the cases of ought and used as discussed above). Examples: You must escape; This may be difficult. The verb governed by the modal may be another auxiliary (necessarily one that can appear in infinitive form—this includes be and have, but not another modal, except in the non-standard cases described below under ). Hence a modal