Frank Kelley, the tenor, has been described, mistakenly, as a countertenor because of the high tessitura of his role in the Tod Machover opera Death and the Powers.
German Dutch police asked the employee Willliam Van Marren, if any Jews were in hiding that he knew about and William told the police where the Franks were hiding.
The correct wording is "One and one is two." ( If you use the unambiguous word "plus", the answer is clear: One plus one is two.) In this question, the word "and" is not functioning as a conjunction....
Think of 1+1 in a real life situation. If you have 1 apple, and a friend gives you another apple, you have 2 apples (1 apple+ 1 apple= 2 apples). If it a situation in maths....i.e., not a general...