I find this book is very interesting

Ha Long Bay is famous for its beautiful limestone island.

1.D

2.B

3.A

4.A

5.C

6.A

7.B

8.B

To me , my best friend is Hao . Hao is 13 years old . She has a long black hair , an oval face , a straight nose and brown eyes . She is the most beautiful girl in my grade . We have been friends for a very long time . The deeper our mutual understanding becomes the more we feel closely attached to each other . HAO AND I are keen on learning . we are the best pupils in our class . HAO IS always at the top . She is good at every subject , but she never show pride in her abilities and always tries to learn harder. HAO family is not rich and Her parents are retired workers . I like Hao very much beacause of her honestly and straight forwarders . SHE is always ready to help her weak friends in their study.. . In my relation with Hao , I have got precious experience : thirst for learning , patience to overcome difficulties and many others

Chất nào sau đây không có khả năng tham gia phản ứng trùng hợp? 

A. Caprolactam.

B. Toluen.

C. Stiren.

D. Acrilonitrin.

Cho l,68g bột sắt và 0,36g bột Mg tác dụng với 375ml dung dịch CuSO₄ khuấy nhẹ cho đến khi dung dịch mất màu xanh, thấy khối lượng kim loại thu được sau phản ứng là 2,82g. Nồng độ mol/1 của CuSO₄ trong dung dịch trước phản ứng là

A. 0,2

B. 0,15M

C. 0,1M

D. 0,05M