Answer:
1. He says he's turned over a new leaf, but I have my doubts.
2. The boss needs an assistant with good knowledge of foreign trade.
Step-by-step explanation:
The given blanks will be filled with the words that best fit the structure and form of the words in the sentences. This means that the required words can be in from the different parts of speech or even the different forms of verbs, whatever fits the blanks well.
The two sentences will be filled as shown below-
1. He says he's turned over a new leaf, but I have my doubts.
In this sentence, "turning over" means changing one's behavior or lifestyle.
2. The boss needs an assistant with good knowledge of foreign trade.
The word "with" is a preposition that means accompanied or joined by another thing.