It was mostly he who talked and he seemed afraid to stop for fear she'd ask him to leave her by herself.

　　An example of a verbal subtest would be vocabulary, whereas an example of a performance subtest would be picture arrangement, the latter requiring an examinee to arrange a set of pictures into a sequence so that they tell a comprehensible story.

　　A body at rest will remain at rest and a body in motion remain in motion at a constant speed in a straight line, unless acted upon by an external force.

　　要点分析和参考译文

　　要点：这是一个由and 连接的并列复合句。And前面的句子是强调句，强调的成分是he.It仅位先行代词，没有意义。Mostly 用作副词，意为“多半”。 For fear（that）= in order that……should not happen意为“生怕……，以免……”。例如：I daren't tell you what he did , for fear that he should be angry with me.（我不敢将他的事告诉你，怕他因此对我发脾气）。To leave her by herself相当于to leave her alone.
　　参考译文：大部分时间都是他在讲话。他似乎害怕停下来，生怕话一停，她就会请他离开。

　　要点：本句由whereas 连接在一起的两个分句并列而成。“the latter requiring an examinee to arrange a set of pictures into a sequence so that they tell a comprehensible story.”是现在分词独立主格结构；“the latter”是现在分词“ requiring”的逻辑主语：“the latter”指的是“ an example of a performance subtest” .“ so that they tell a comprehensible story” 是“so that” 引导的目的状语从句；其中主语“they”指的是：“a set of pictures”
　　参考译文：口头语言测试的一个实例是测验词汇能力，而行为表现测试的实例是测验排列图画能力。后者要求受测试者把一组图画排序，这个次序应该能够表达一个可以理解的故事。

　　要点：这是一个并列复合句。And 连接两个句子，构成并列句。Unless 是连词，连接下一个子句，做前面两个主句的状语从句。Unless 后面省略了it is.At rest和in motion 是两个介词短语，分别作body的定语，意思为“处于静止状态”和“处于运动状态中”
　　参考译文：除非受到外力作用，静止的物体将继续保持静止，运动的物体将继续作匀速直线运动。