• The scientist must assure himself that the errors are stated on a reasonable basis.
• Check that the liquid is of the correct specific gravity.
• Fuel injectors should be (carefully) tested to determine that they are functioning properly.
• Ensure that the mains supply is switched off.
• Make ( or Be ) sure that the voltage selector is set correctly.
• See ( to it ) that the face against which the leather fits is quite clean.
• In order to make certain that a parent tree will produce offspring with ...
• Thus Kepler satisfied himself that the orbit was oval.
• By recalculating vu 2 we were able to verify ( or ascertain ) that the approach of this section is consistent with ...
• To convince yourself that this is correct, use appropriate unity factors.