- has an obligation to do
- Has to
- of Shall
- Used as an auxiliary verb, to express a conditional or
contingent act or state, or as a supposition of an actual fact; also,
to express moral obligation (see Shall); e. g.: they should have come
last week; if I should go; I should think you could go.
- Be obliged to
- Has to
- Is obliged to
- Is obliged to mould
- Necessity
- New wine
- Prerequisite