【简答题】Explain why addition of HNO 3 to concentrated H 2 SO 4 results in the formation of and ions. How could one test experimentally to confirm that such ions exist in H2SO4 solution?
【单选题】Which of the following promises constitutes sufficient consideration in the formation of a contract?
A.
To reimburse the cost of refurbishing a house where the promise in made after the refurbishing has been completed
B.
To lease a house at an annual rent significantly below current market rates
C.
To pay a witness an agreed monetary sum in exchange for attending court
D.
To pay a worker extra remuneration in exchange of continuing to perform their existing contractual duties
【单选题】In the rostrocaudal patterning of nervours system, which of the following molecule plays a key role in the formation of MHB.
【单选题】判别下列荷载中哪些属于活荷载? I土压力;Ⅱ风荷载;Ⅲ积灰荷载;Ⅳ结构自重
【单选题】Participating in the formation of the median sulcus of the forearm is ( )