I 主语
took my first uneasy look at 谓语,took a look at 看一眼的变体,中间用形容词,去掉了a；
what was to be my only means of transportation for several hours.整句话是what 引导的宾语从句,做at的宾语；
在从句中,what 是主语,was是谓语,to be my only means of transportation for several hours.是表语.
翻译：我不舒服地看了将要成为我几小时中唯一的交通方式的东西第一眼.
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补充：1.take my first uneasy look at 意思是我不情愿地看了第一眼
2.means 这里的意思是 方式,方法,my only means of transportation 意思是 我唯一的交通方式