Texans above all are optimists, and few of them seem to doubt that Mexico's proximity is a huge long-term source of strength for the Lone Star state.

德州人都是乐观主义者，他们对于邻近的墨西哥会是这个孤星州长期的巨大的力量来源深信不疑。

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This agent lost this sale as a result of his high level of prospect service, but by continuing that high level of prospect service, might have gained a long-term source of quality referrals.

FORBES: Prospect Service: Applying a Great Customer Servicing Mindset to Lead Nurturing

In a section on energy, he says: "It goes without saying that a secure and affordable supply of energy is essential to everything we do, " adding that "the Severn Barrage offers the possibility of both a long term source of energy and extraordinary economic regeneration".

BBC: Heseltine claims Severn barrage could boost economy

The scheme has also attracted interest as a possible long-term power source for a manned mission to Mars.

ECONOMIST: Nuclear power