direct selling (n. phr.) 直接銷售，直接向客戶行銷和配送產品或服務，而不經由外部或第三方銷售代表的銷售方式。 indirect selling (n. phr.) 間接銷售，經由外部或第三方銷售代表，進行產品或服務的行銷和配送。 over-the-counter (a.) 櫃檯買賣的；店面交易的，如同字面意思，指透過櫃檯做出金錢換取商品之交易。 direct mail (n. phr.) 直接郵寄廣告，即所謂DM，經由郵寄贈送等形式，將產品或服務相關資訊送到給消費者手中的一種行銷方法。 marketing (n.) 行銷，推銷、銷售和分配一項產品或服務的手法或技巧。 third-party (a.) 第三方的，除了製造商和客戶以外的人或個體的。 affiliate (n.) 聯（加）盟行銷，銷售行為中為產品尋找潛在客戶，或為其宣傳，但不進行產品配送行為的個人或組織。 reseller (n.) 經銷商，銷售行為中，買入產品並於日後銷售以獲利的個人或組織。 sales representative (n. phr.) 業務代表，代表公司從事產品銷售的人，簡稱sales rep。sales：銷售的；有關銷售的 distribution (n.) 配銷；分銷；經銷，商品從製造商轉移到客戶端的過程。 established channel (n. phr.) 既定銷售管道，於某重要時期已成功使用過的行銷或配送方式。 sales outsourcing (n. phr.) 銷售外包，與第三方締結契約，委託其找出潛在客戶並完成銷售之行為。
Imagine finding yourself in a secret cave deep beneath the earth's surface. You blink to try to adjust your eyes to the darkness, but it's no use. You can't see a thing. The air around you is extremely humid and you feel a bit uncomfortable. All of a sudden, you remember that you brought a flashlight. You turn it on and can't believe your eyes. There are giant crystals everywhere. Some are clear, others are light blue, and all of them tower above you. You could explore the cave for hours.
Although this sounds like a place that can exist only in the human imagination, it's as real as Mount Everest or Ha Long Bay in Vietnam. This is the Giant Crystal Cave in Naica, Mexico. The cave is nearly 300 meters beneath the earth's surface. It's full of giant crystals that are made out of selenite. Some of these crystals are as large as 12 meters in length. The crystals are so big because of their unique environment. They have been in very hot water for over 500,000 years.
Before you book a plane ticket to Mexico, there's one thing you should know. Unfortunately, the cave is not open to the public. The atmosphere inside the cave is hot enough to kill you. Temperatures can be as high as 58 degrees Celsius. Thus, anyone exploring the cave needs to wear special protective equipment.
Even the professionals with protective gear won't be able to enjoy the cave for long. Exposure to air has a damaging effect on the giant crystals. Therefore, the organization that is responsible for the cave plans to flood it with water after enough photos and videos have been taken.