例句與造句

1. This small group of viruses, exemplified by the Hepatitis B virus, have a double-stranded, gapped genome that is subsequently filled in to form a covalently closed circle ( ccc DNA ) that serves as a template for production of viral mRNAs and a subgenomic RNA . The pregenome RNA serves as template for the viral reverse transcriptase and for production of the DNA genome.
2. It's difficult to find pregenome in a sentence. 用pregenome造句挺難的