Answer:
1. Allan spoke with grudging acceptance of Lalla's engagement to Godfrey. <em><u>vacillating</u></em>.
2. Jane knew she would feel very lonely after Lalla got married. <em><u>bereft </u></em>
3. Mother was exasperated with Lalla for changing her mind so often about the wedding plans. <em><u>resignation </u></em>
4. For Lalla's sake, Godfrey and Allan put aside their intense dislike for each other." <em><u>enmity </u></em>
5. On the wedding day the weather turned sunny and mild. <em><u>Benign </u></em>
6. Before the ceremony, Uncle Peter spoke distressingly to Godfrey about the responsibilities of married life. <em><u>unnervingly </u></em>
7. Remembering Uncle Peter's advice, Godfrey felt some anxiety about getting married. <u><em>trepidation </em></u>
8. Aunt Fran arrived wearing a very silly green feathered hat. <em><u>ludicrous </u></em>
9. Allan missed the wedding because he could not figure out the map Barney sent him. <em><u>decipher </u></em>
10. The ceremony went exactly as planned, and the organist played the wedding music without a single mistake. <em><u>impeccably</u></em>
Explanation:
1. Allan spoke with grudging acceptance of Lalla's engagement to Godfrey. vacillating- it means to hesitate, to be unable to come to terms with.
2. Jane knew she would feel very lonely after Lalla got married. bereft means to be left alone, to be all alone.
3. Mother was exasperated with Lalla for changing her mind so often about the wedding plans. resignation- it means to give up, to be done with.
4. For Lalla's sake, Godfrey and Allan put aside their intense dislike for each other." enmity- means to have animosity, hatred or dislike for something.
5. On the wedding day the weather turned sunny and mild. Benign- means gentle, friendly.
6. Before the ceremony, Uncle Peter spoke distressingly to Godfrey about the responsibilities of married life. unnervingly- means making someone feel uncomfortable, or giving the feeling of unwelcome, or a worried feeling.
7. Remembering Uncle Peter's advice, Godfrey felt some anxiety about getting married. trepidation- means to feel anxious or nervous about something.
8. Aunt Fran arrived wearing a very silly green feathered hat. ludicrous- this word suggests something that is outrageous, unreasonable.
9. Allan missed the wedding because he could not figure out the map Barney sent him. decipher- means to understand, to get the main point, to solve, etc.
10. The ceremony went exactly as planned, and the organist played the wedding music without a single mistake. impeccably- It means perfect, with no faults or mistakes.