sentences:  Unlike Army Reserve members, National Guard members cannot be mobilized individually (except through voluntary transfers and Temporary Duty Assignments "TDY"), but only as part of their respective units.However, there has been a significant number of individual activations to support military operations.For much of the final decades of the twentieth century, National Guard personnel typically served "one weekend a month, two weeks a year", with a portion working for the Guard in a full-time capacity.