1. The word whose underlined part differs in pronunciation from the other three is **D. clay**. (The underlined parts of "appliance," "generate," and "elevator" all have a long vowel sound, while "clay" has a different sound.)

2. The word that differs from the other three in the position of the main stress is **B. generate**. (In "assistant," "furniture," and "monitor," the main stress is generally placed on the second syllable, while "generate" has the stress on the first syllable.)