语法图解
探究发现
①Antarctica is the coldest place on Earth.
②They call it AntiArktikos, or Antarctica ...
③98% of the surface is covered permanently in the ice cap.
④To learn a foreign language well is not easy.
⑤Swimming is a good exercise.
⑥Whether he will come is doubtful.
⑦It is difficult to imagine a more inhospitable place.
⑧I hope to see you soon.
⑨He came in and sat down.
⑩The student went pale when he saw the teacher.
?I can easily tell my father's step.
?We hadn't walked far when we lost our way.
[我的发现]
(1)①～⑥句中的黑体部分在句中均作主语。
(2)由④⑤⑥句可知，不定式、动词ing形式、从句作主语时谓语动词通常要用单数形式。
(3)⑦句中用it作形式主语。
(4)⑧～?句中，黑体部分均为动词，且⑧⑨句中的动词可直接作谓语，而⑩??句中的黑体部分不能单独作谓语。
