题干
Teddy came to my _____ with a cheque of $200 to pay my room rate, after I told him that my wallet had been stolen.
A：attendance
B：assistance
C：rescue
D：safety
答案(点此获取答案解析）
B
Cl、
Cl两种同位素，若知氯元素的相对原子质量为35.5，则