课文详注 Further notes on the text
1．Every time he wanted to come into the garden he would bark until someone opened the gate.每当它想到花园里来时，便汪汪叫个不停，直到有人把门打开。
every time在这里为连词引导一个时间状语从句，表示“每次”、“每当”，主句中的would表示过去的习惯性动作。用一般过去时的句子中它们经常连用：
Every time we met, we would talk for a while.
我们每次见面都要聊一会儿。
Every time he came to the restaurant, he would first ask for a cup of tea.
他每次到这个饭馆来，都是先要一杯茶。
2．…my husband spent weeks training him to press his paw on the latch to let himself in.……我丈夫花了几个星期的时间训练它用脚爪按住门闩把自己放进来。
（1）spend表示“在……上花时间”时，后面如果跟名词则用介词on;如果跟动名词则用介词in（在口语中in往往省略）：
Why don't you spend more time on studies?
你为什么不在学习上再多花点时间呢？
I spent two weeks(in) reading this book.
我花了两星期的时间读这本书。
（2）train的宾语是him, to press…是宾语补足语，to let…为目的状语。
3．Rex soon became an expert at opening the gate.雷克斯很快成了开门的专家。
expert表示“做/干……的专家/高手”时后面通常用 at doing sth.;表示在某一领域是“专家”、“权威”时可用介词in或on:
John is an expert at driving a car.
约翰是开车高手。
She is an expert in flowers.
她是花卉方面的专家。
Sam is an expert on that problem.
萨姆是研究那个问题的权威。
4．This time he was barking so that someone would let him out!这次它叫着让人把它放出去！
连词so that引导的是目的状语从句。（cf．本课语法）
语法 Grammar in use
1．复习第50～58课语法
2．表示目的的几种方式：to, in order to, so as to, so that, in order that
（1）带to的不定式及其变体in order to和so as to 可以用来表示目的：
I went to live in France to/in order to/so as to learn French.
我去法国居住，以便学习法语。
not to可以用于表示取舍：
I went to France not to study French, but to study chemics.
我去法国不是为了学法语，而是为了学化学。
so as not to/in order not to可以用于表示“以防”：
I shut the door quietly, so as not to/in order not to wake the baby.
为了不惊醒婴儿，我轻轻地关上门。
在bring, buy, need, take, use, want等动词后经常用宾语+不定式（而不用宾语+in order to/so as to），不定式表示用宾语的目的：
I want something to drink.
我想要一点喝的东西。
I need a spoon to eat this ice cream with.
我需要一把汤匙来吃这冰淇淋。
Bring me a chair to sit on.
给我拿一把椅子来坐。
（2）连词 so that, in order that可以引导目的状语从句。当主句用一般现在时、现在完成时或一般将来时的时候，so that和 in order that后面可以跟may, can或will。so that比in order that更为普遍：
I've arrived early so that/in order that I may/can/will get the tickets.
我到得早，以便能买到票。
当主句中的动词为一般过去时、过去进行时或过去完成时的时候， so that和in order that后面跟should, could, might或would:
I arrived early so that/in order that I should/could/might/would get the tickets.
（译文同上）
so that和in order that后面的否定形式如下：
I arrived early so that/in order that I might not miss anything.
我到得很早，以免错过什么。（否定句中不可用could,可用should, would等）
（3）相比之下，带to, so as to和 in order to的结构比带that的结构要简单、自然，所以多为人使用：
I arrived early so as not to/in order not to miss anything.（译文同上）
当前后主语不一致时，不定式前面加for+名词/代词比that结构更简洁