翻译题：中囯政府宣布每年的8月8日为“全民健身日”(National Fitness Day)，推动全民健身。这一举动不仅在全国范围内普及了健康理念，还使人们锻炼的方式更加多样化。 每天早晨，喜欢户外运动的老年人会聚集(congregate)在公园里锻炼身体，如打太极拳(tai chi)、跳彩带舞(ribbon dancing)等。公园里那些低冲击力的公共健身器材和新鲜的空气十分适合他们。 相反，年轻人则发起了一股室内健身热潮。比起户外活动，他们更喜欢选择华丽的健身房。在他们看来，健身房既时尚又

AThe problem of extracting methane hydrates is retrieving methane gas and bringing it to the surface.

BIt is very easy to find methane hydrates.

COnly Japan wants to extract methane hydrates.

DMethane hydrates are a major source of fuel in Japan.

AThey grow in seawater.

BThey grow more slowly than other trees.

CThey grow good-quality fruits.

DThey are ideal for shade.

ATropical climate.

BPolitical unrest.

CFood crisis.

DDisease.