# ruff: noqa: E731, E741
import sys

read = sys.stdin.readline
input = lambda: read().rstrip()
ir = lambda: int(read())
rir = lambda: range(int(read()))
mir = lambda: map(int, read().split())
lmir = lambda: list(map(int, read().split()))


def solve():
    n = ir()
    if n % 2 == 0:
        return [(i ^ 1) + 1 for i in range(n)]
    else:
        res = [(i ^ 1) + 1 for i in range(n - 3)]
        res.append(n - 1)
        res.append(n)
        res.append(n - 2)
        return res


def main():
    for _ in rir():
        print(*solve())


def test():
    pass


if __name__ == "__main__":
    if sys.stdin.isatty():
        test()
    else:
        main()