outline

1.an outline和outlines往往意思相同。例如：This book gives an outline（或outlines）of the subject.

2.注意下面各句里的in outline, in clear outline和in broad outline里都没有a（或an）：

• This is a map of China in outline.
• The drawings must be in clear outline.
• The book delineates in broad outline the fundamental of Acupunctural Anaesthesia.