用括号内所给单词的适当形式填空。

1. The red T-shirt is on _____ ( sell) for ten yuan.    

2. The girl plays basketball very_____ ( good).    

3. The music sounds very _____ (well).    

4. We can see many _____ (strawberry) on the desk.    

5. -Well, let's play baseball.             

    -That sounds _____ ( well) .    

6. These are Linda's _____ (parent).    

7. My name is Mona Black. Mona is my _____ (one) name.    

8. This _____ (be) Gina's sister.    

9. Thank you for _____ (help) us.    

10. Where _____ (be) your Chinese books?

下列有关³₂He和⁴₂He的说法不正确的是[ ]

A．⁴₂He在一定条件下若转变为³₂He，不属于传统意义上的化学变化

B．³₂He和⁴₂He的核外电子数均为2

C．³₂He和⁴₂He分别形成单质的物理和化学性质完全一样

D．³₂He和⁴₂He互为同位素