例句與造句

1. These coal deposits are sufficiently thick, and are located under sufficiently thin overburden, as to be economically viable.
2. The Alum Bluff Group has an outcropping beneath a thin overburden in the western panhandle from river valleys in Okloosa County eastward to western Jackson County.
3. It's difficult to find thin overburden in a sentence. 用thin overburden造句挺難的