超亲优势（over-parent heterosis）

Being a parent is not always easy, and being the parent of a child with special needs often carries with （）extra stress.

A:it B:them C:one D:him

Being a parent is not always easy, and being the parent of a child with special needs often carries with （）extra stress.

A:it B:them C:one D:him

Being a parent is not always easy, and being the parent of a child with special needs often carries with（）extra stress.

A:it B:them C:one D:him

"The parent book is______．

A:the Sailing Directions B:the Corrections to Sailing Directions in force C:The Annual Summary of Notice to Mariners D:The Weekly Edition"

"If the corrections be stuck in the parent book or current supplement, ______．

A:when a new supplement is received, those corrections issued after the date of the newsupplement must be retained B:the parent book must be consulted C:the current supplement must be consulted D:the Annual Summary of Notice to Mariners must be used