读课文《我们的知识是有限的》，填上关联词：

故此，____我不能准确地断定彗星的形成之因，____我是应当受到宽宥的，____我从未声言能够做到这一点，____我懂得它会以某种不同于我们任何臆度的方式形成。

    Driving in Canada is similar to driving in many parts of the United States. Distances and speeds, however, are posted in kilometers per hour and some signs, particularly in Quebec, may only be in French.

    Unless otherwise posted, the maximum (最大限度的) speed limit in Canada is 50km/hr in cities and 80km/hr on highways. On rural highways, the posted speed limit may be 100km/hr. It is illegal to take automobile radar detectors (汽车雷达检测器) into Quebec, Ontario, Manitoba, and the Yukon. Seat belt use is required by law for all passengers, and child car seats must be used by children under 40 pounds. Some provinces require drivers to keep their vehicles' headlights on during the day and some have banned (禁止) driving while using a hand-held cell phone. Motorcycles cannot share a lane (车道), and safety helmets for motorcycle riders and passengers are necessary. Running a red light is a serious crime throughout Canada and drivers are advised to stop before starting when a light turns green.

    Winter travel can be dangerous due to heavy snowfalls and icy conditions. Some roads and bridges are often closed in winter. Snow tires are required in some provinces. Travelers should also be careful about animals while driving at night in rural areas.

    Highway 401, from Detroit to Montreal, is one of the busiest highways in North America. It has been the scene of many deadly traffic accidents due to sudden and severe weather changes, high rates of speed, and heavy truck traffic. Thus drivers should be alert while travelling here.

    Please refer to our Road Safety page for more information. Also, we suggest that you visit the website of Canada's national authority responsible for road safety.

阅读材料，回答问题。

“乘风破浪会有时，直挂云帆济沧海”。同心逐梦的中国，正在以博大宽广的胸怀、心系天下的情怀，奏响“一带一路”交响曲，谱写自贸区战略新华章。

材料一  2013年，中国******提出共建“丝绸之路经济带”和“21世纪海上丝绸之路”（简称“一带一路”）的倡议，得到了沿线国家和地区的热烈响应。2015年3月，福建被国家定位为“21世纪海上丝绸之路核心区”。2015年4月，中国（福建）自由贸易试验区（简称福建自贸区）正式建立，实施范围涵盖平潭、厦门和福州三个片区。

材料二  依法治国是实现国家治理体系和治理能力现代化的必然要求。自2013年以来，在党中央领导下，全国人大健全法制，国务院统筹协调，各有关部门协同实施，社会各界群策群力，福建自贸区筹建工作依法有序推进。目前，福建省围绕立足两岸、服务全国、面向世界的战略要求，确立了自贸区重点实验项目186项，涉及体制创新、对台开放、投资管理、法制保障、市场监管等方面，自贸区建设全面铺开。

材料三  一部海上丝绸之路的发展史，既是中华民族走向海洋、走向世界的历史，也是东西方经济文化交流互动、共生共荣的历史。共建21世纪海上丝绸之路，是一条开放合作、和谐包容、互利共赢之路。对此，同学们围绕“经济和文化何者先行”展开讨论。